TRH and Rifaximin – an alternative to intranasal TRH or oral Taltirelin/Ceredist?

I think this is going to be one of my smarter posts. It may be more for our doctor readers and our motivated home-based researchers. It does remain a hypothesis and while it looks plausible it is certainly not 100% proven – so typical Peter stuff.

Many parents with autism regularly treat their child with the antibiotic Rifaximin. This drug is also the go-to therapy for SIBO (small intestine bacterial overgrowth) and is a key part of the Nemechek autism protocol to increase butyric acid production in the gut (and reduce propionic acid).

Some parents report that their child with completely normal GI function responds well behaviorally to Rifaximin.

Rifaximin is taken orally and stays in the gut, it does not enter the blood stream.

Our long-time reader Maja mentioned that she still uses Rifaximin in her now adult daughter.

I then did a quick Google and was surprised to see Rifaximin linked to the hormone TRH.

And, most surprising, you can use Rifaximin to treat prostate inflammation, via its effect on TRH.

TRH was the subject of an experiment I did 12 years ago. I suggested that an existing Japanese drug, an orally available TRH super-agonist, could be repurposed at a low dose to treat autism.

 https://www.epiphanyasd.com/2014/05/the-peter-hypothesis-of-trh-induced.html

I then noted that a well-known, but a little controversial, doctor in the US used intranasal TRH to treat his patients with chronic fatigue syndrome.

Another doctor had grant funding from the US military to develop intranasal TRH to reduce suicides in veterans.

In my old post I started by wondering why my son and some others with severe autism respond so well to sensory stimulation like standing on the upper deck of a ferry boat in the open sea on a windy day, or sitting in an open-top bus, driving in a convertible car etc.

Without be able to do any testing I looked for “similar” situations that haven been studied. The closest I found was people jumping out of a plan (with a parachute) where one of the key changes was a surge in the level of the hormone prolactin.

How to replicate the open-top bus effect? One of my doctor relatives suggested sitting Monty in front of a fan. Over course I wanted better than that. I found that stimulating TRH receptors in the brain would release prolactin.  It was already known that TRH is disturbed in autism.

It seemed to me that a Japanese orphan drug developed to treat spinocerebellar degeneration (SCD) – a group of progressive neurodegenerative disorders characterized by ataxia (poor coordination, gait disturbance, speech difficulties) could be repurposed.

I did discuss with a Japanese doctor in Osaka and he prescribed it.

It is a very expensive drug, even when bought with a prescription, and it has a very short expiry date. The idea was to use a micro-dose, to avoid undesirable side effects and this would also make the price less scary. I thought it provided a benefit without side effects, but was impractical. At the full dose it is potent and is the only drug I have trialed that had a near immediate profound effect on myself. I suddenly had hyper-acute vision. The micro dose had no effect on me.

Since Ceredist (taltirelin) is a TRH analogue, it could in theory affect the hypothalamic–pituitary–thyroid (HPT) axis.

TRH normally stimulates TSH release from the pituitary, which then increases thyroid hormone (T4/T3) secretion. Taltirelin was designed for CNS activity rather than endocrine use. Its clinical development in Japan for spinocerebellar degeneration focused on neurological symptoms, not thyroid stimulation. Animal studies showed that taltirelin has much weaker TSH-releasing activity than native TRH, but much stronger central nervous system stimulant effects (improved motor coordination, wakefulness).

Human data at therapeutic doses for spinocerebellar degeneration, significant changes in thyroid hormone levels (TSH, T3, T4) have not been a common clinical issue. Monitoring thyroid function is not part of standard Ceredist treatment.

 

So what is TRH?

TRH (thyrotropin-releasing hormone) serves as a master regulator of energy metabolism, mood, arousal, cognition, and immune balance.

Core Endocrine Role

Produced in the hypothalamus (paraventricular nucleus), but also found in other brain regions and peripheral tissues.

Main function is to stimulate the anterior pituitary to release TSH (thyroid-stimulating hormone), this increases thyroid hormone (T3, T4) production in the thyroid gland.

A secondary effect promotes prolactin release from the pituitary. TRH is a significant stimulator, especially when dopamine inhibition is reduced.

 

Effects on Other Hormones

Growth hormone & insulin: Some modulatory effects reported in stress and metabolism, though less central.

ACTH/cortisol: Minor indirect effects; TRH can modulate stress responses via cross-talk with the HPA axis.

 

Mood and Behavior

Antidepressant effects - TRH has rapid mood-elevating and activating effects in both animals and humans, independent of thyroid hormones. Some clinical studies have tested TRH or TRH analogs as rapid-acting antidepressants.

Arousal & vigilance - it increases wakefulness, motivation, and locomotor activity.

Anxiety - can produce mild anxiogenic effects at high doses, but generally associated with improved mood and alertness.

 

Cognition

Neurotransmitter modulation - TRH interacts with cholinergic, dopaminergic, and glutamatergic systems.

Memory & learning - TRH and TRH-like peptides enhance memory consolidation and counteract cognitive decline in animal studies.

Neuroprotection - shown to reduce neuronal injury in models of ischemia and trauma.

 

Inflammation & Immunity

 Anti-inflammatory - TRH dampens pro-inflammatory cytokine production (e.g., TNF-α, IL-1β).

Microglia modulation - TRH reduces microglial over-activation, relevant in neuroinflammation.

Systemic effects: TRH analogs show protective roles in sepsis and multiple organ injury in animal studies, likely via immune regulation and mitochondrial support.

 

Here is the recent study that showed the common antibiotic Rifaximin increases TRH in the brain and in peripheral tissues. Rifaximin itself stays within the gut when taken by mouth, it does not enter the blood stream. It changes the gut microbiota which then sends a signal via vagus nerve to the brain (clever, isn’t it?).

Caveat – rats are not humans.

 

Rifaximin modulates TRH and TRH-like peptide expression throughout the brain and peripheral tissues of male rats

 

The TRH/TRH-R1 receptor signaling pathway within the neurons of the dorsal vagal complex is an important mediator of the brain-gut axis. Mental health and protection from a variety of neuropathologies, such as autism, Attention Deficit Hyperactivity Disorder, Alzheimer’s and Parkinson’s disease, major depression, migraine and epilepsy are influenced by the gut microbiome and is mediated by the vagus nerve. The antibiotic rifaximin (RF) does not cross the gut-blood barrier. It changes the composition of the gut microbiome resulting in therapeutic benefits for traveler’s diarrhea, hepatic encephalopathy, and prostatitis. TRH and TRH-like peptides, with the structure pGlu-X-Pro-NH₂, where “X” can be any amino acid residue, have reproduction-enhancing, caloric-restriction-like, anti-aging, pancreatic-β cell-, cardiovascular-, and neuroprotective effects. TRH and TRH-like peptides occur not only throughout the CNS but also in peripheral tissues. To elucidate the involvement of TRH-like peptides in brain-gut-reproductive system interactions 16 male Sprague–Dawley rats, 203 ± 6 g, were divided into 4 groups (n = 4/group): the control (CON) group remained on ad libitum Purina rodent chow and water for 10 days until decapitation, acute (AC) group receiving 150 mg RF/kg powdered rodent chow for 24 h providing 150 mg RF/kg body weight for 200 g rats, chronic (CHR) animals receiving RF for 10 days; withdrawal (WD) rats receiving RF for 8 days and then normal chow for 2 days.

Results

Significant changes in the levels of TRH and TRH-like peptides occurred throughout the brain and peripheral tissues in response to RF. The number of significant changes in TRH and TRH-like peptide levels in brain resulting from RF treatment, in descending order were: medulla (16), piriform cortex (8), nucleus accumbens (7), frontal cortex (5), striatum (3), amygdala (3), entorhinal cortex (3), anterior (2), and posterior cingulate (2), hippocampus (1), hypothalamus (0) and cerebellum (0). The corresponding ranking for peripheral tissues were: prostate (6), adrenals (4), pancreas (3), liver (2), testis (1), heart (0).

Conclusions

The sensitivity of TRH and TRH-like peptide expression to RF treatment, particularly in the medulla oblongata and prostate, is consistent with the participation of these peptides in the therapeutic effects of RF. 

 

It turns out that other researchers have looked at Rifaximin’s effects on the brain, but they never understood the mechanism.

 

Effects of Rifaximin on Central Responses to Social Stress—a Pilot Experiment

Probiotics that promote the gut microbiota have been reported to reduce stress responses, and improve memory and mood. Whether and how antibiotics that eliminate or inhibit pathogenic and commensal gut bacteria also affect central nervous system functions in humans is so far unknown. In a double-blinded randomized study, 16 healthy volunteers (27.00 ± 1.60 years; 9 males) received either rifaximin (600 mg/day) (a poorly absorbable antibiotic) or placebo for 7 days. Before and after the drug intervention, brain activities during rest and during a social stressor inducing feelings of exclusion (Cyberball game) were measured using magnetoencephalography. Social exclusion significantly affected (p < 0.001) mood and increased exclusion perception. Magnetoencephalography showed brain regions with higher activations during exclusion as compared to inclusion, in different frequency bands. Seven days of rifaximin increased prefrontal and right cingulate alpha power during resting state. Low beta power showed an interaction of intervention (rifaximin, placebo) × condition (inclusion, exclusion) during the Cyberball game in the bilateral prefrontal and left anterior cingulate cortex. Only in the rifaximin group, a decrease (p = 0.004) in power was seen comparing exclusion to inclusion; the reduced beta-1 power was negatively correlated with a change in the subjective exclusion perception score. Social stress affecting brain functioning in a specific manner is modulated by rifaximin. Contrary to our hypothesis that antibiotics have advert effects on mood, the antibiotic exhibited stress-reducing effects similar to reported effects of probiotic

 

Effects of the antibiotic rifaximin on cortical functional connectivity are mediated through insular cortex

It is well-known that antibiotics affect commensal gut bacteria; however, only recently evidence accumulated that gut microbiota (GM) can influence the central nervous system functions. Preclinical animal studies have repeatedly highlighted the effects of antibiotics on brain activity; however, translational studies in humans are still missing. Here, we present a randomized, double-blind, placebo-controlled study investigating the effects of 7 days intake of Rifaximin (non-absorbable antibiotic) on functional brain connectivity (fc) using magnetoencephalography. Sixteen healthy volunteers were tested before and after the treatment, during resting state (rs), and during a social stressor paradigm (Cyberball game—CBG), designed to elicit feelings of exclusion. Results confirm the hypothesis of an involvement of the insular cortex as a common node of different functional networks, thus suggesting its potential role as a central mediator of cortical fc alterations, following modifications of GM. Also, the Rifaximin group displayed lower connectivity in slow and fast beta bands (15 and 25 Hz) during rest, and higher connectivity in theta (7 Hz) during the inclusion condition of the CBG, compared with controls. Altogether these results indicate a modulation of Rifaximin on frequency-specific functional connectivity that could involve cognitive flexibility and memory processing.

  

Probing gut‐brain links in Alzheimer's disease with rifaximin

Gut‐microbiome‐inflammation interactions have been linked to neurodegeneration in Alzheimer's disease (AD) and other disorders. We hypothesized that treatment with rifaximin, a minimally absorbed gut‐specific antibiotic, may modify the neurodegenerative process by changing gut flora and reducing neurotoxic microbial drivers of inflammation. In a pilot, open‐label trial, we treated 10 subjects with mild to moderate probable AD dementia (Mini‐Mental Status Examination (MMSE) = 17 ± 3) with rifaximin for 3 months. Treatment was associated with a significant reduction in serum neurofilament‐light levels (P < .004) and a significant increase in fecal phylum Firmicutes microbiota. Serum phosphorylated tau (pTau)181 and glial fibrillary acidic protein (GFAP) levels were reduced (effect sizes of −0.41 and −0.48, respectively) but did not reach statistical significance. In addition, there was a nonsignificant downward trend in serum cytokine interleukin (IL)‐6 and IL‐13 levels. Cognition was unchanged. Increases in stool Erysipelatoclostridium were correlated significantly with reductions in serum pTau181 and serum GFAP. Insights from this pilot trial are being used to design a larger placebo‐controlled clinical trial to determine if specific microbial flora/products underlie neurodegeneration, and whether rifaximin is clinically efficacious as a therapeutic.

 

Rifaximin and the prostate

For some reason one of the main areas where Rifaximin triggers the production of TRH is in the prostate, in males. There are studies showing how Rifaximin can be used to treat prostatitis (prostate inflammation).

Symptom Severity Following Rifaximin and the Probiotic VSL#3 in Patients with Chronic Pelvic Pain Syndrome (Due to Inflammatory Prostatitis) Plus Irritable Bowel Syndrome

This study investigated the effects of long-term treatment with rifaximin and the probiotic VSL#3 on uro-genital and gastrointestinal symptoms in patients with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) plus diarrhoea-predominant irritable bowel syndrome (D-IBS) compared with patients with D-IBS alone. Eighty-five patients with CP/CPPS (45 with subtype IIIa and 40 with IIIb) plus D-IBS according to the Rome III criteria and an aged-matched control-group of patients with D-IBS alone (n = 75) received rifaximin and VSL#3. The primary endpoints were the response rates of IBS and CP/CPPS symptoms, assessed respectively through Irritable Bowel Syndrome Severity Scoring System (IBS-SSS) and The National Institute of Health Chronic Prostatitis Symptom Index (NIH-CPSI), and performed at the start of therapy (V0) and three months after (V3). In IIIa prostatitis patients, the total NIH-CPSI scores significantly (p < 0.05) decreased from a baseline mean value of 21.2 to 14.5 at V3 , as did all subscales, and in the IIIb the total NIH-CPSI score also significantly decreased (from 17.4 to 15.1). Patients with IBS alone showed no significant differences in NIH-CPSI score. At V3, significantly greater improvement in the IBS-SSS and responder rate were found in IIIa patients. Our results were explained through a better individual response at V3 in IIIa prostatitis of urinary and gastrointestinal symptoms, while mean leukocyte counts on expressed prostate secretion (EPS) after prostate massage significantly lowered only in IIIa cases. 

Since SIBO is treated by rifaximin, some researchers linked SIBO with prostatitis: 

Chronic prostatitis and small intestinal bacterial overgrowth: is there a correlation?

Background: Clinical management of chronic inflammation of prostate and seminal vesicles is very complex. Among the causes of recurrent chronic prostatitis (CP), a possible malabsorption, such as lactose intolerance, in turn related to small intestinal bacterial overgrowth (SIBO), should be considered.

Methods: We have performed lactose and lactulose breath test (BT) in 42 patients with CP, in order to evaluate the prevalence of SIBO in this kind of patients and the concordance of the two tests.

Results: A positive lactulose BT was present in 33/42 patients and in 73% (24/33) was associated to lactose malabsorption. Five patients had positive response after lactulose, while only 4 had both negative tests.

Conclusions: Our data showed an association between lactose and lactulose BT positivity. They also indicated high prevalence of bacterial colonization of small bowel in patients with CP, possibly related to recurrence or chronicity of genitourinary tract inflammation. The research for these phenomena could be relevant in diagnostic route of infertile patients in whom slight gastro-enteric symptoms can be underestimated.

 

For those of you who still read books:

 

Betrayal by the Brain: The Neurologic Basis of Chronic Fatigue Syndrome, Fibromyalgia Syndrome, and Related Neural Network Disorders
This seminal work presents Dr. Goldstein's theory that CFS and fibromyalgia result from dysfunctions in neural networks. It integrates neuroscience research into the pathophysiology and treatment of these conditions.

A Companion Volume to Dr. Jay A. Goldstein's Betrayal by the Brain: A Guide for Patients and Their Physicians
Authored by Katie Courmel, this companion guide simplifies Dr. Goldstein's theories and treatment protocols for a broader audience, aiding patients and physicians in understanding and applying his methods.

 Tuning the Brain: Principles and Practice of Neurosomatic Medicine

In this book, Dr. Goldstein outlines the principles of neurosomatic medicine, a field he developed that combines neurology, psychiatry, and pharmacology to treat chronic illnesses.

In Tuning the Brain: Principles and Practice of Neurosomatic Medicine, Dr. Jay A. Goldstein discusses the use of thyrotropin-releasing hormone (TRH) in treating chronic fatigue syndrome (CFS) and related disorders. He describes TRH as a neuropeptide that can modulate neural network activity, particularly through the trigeminal nerve, which is involved in sensory processing. By stimulating this pathway, TRH may help "re-tune" the brain's response to sensory input, potentially alleviating symptoms associated with CFS and similar conditions.

The book outlines the principles of neurosomatic medicine, a field Dr. Goldstein developed that combines neurology, psychiatry, and pharmacology to treat chronic illnesses. It emphasizes the rapid modulation of neural networks through pharmacological means, aiming to restore normal sensory processing and alleviate symptoms.

 

Conclusion

It does look like Rifaximin has interesting effects beyond where it can reach itself.

Rifaximin → modifies gut microbiota → activates vagus nerve

Vagus nerve → signals to brainstem → hypothalamus → TRH release 

According to that rat study, TRH and TRH-like peptides are present in the prostate, and their levels change in response to rifaximin. The TRH (or TRH-like peptides) in the prostate is produced locally in the prostate tissue itself, not delivered there from the brain via the bloodstream. the level of production can be modulated by gut–brain signaling, such as after rifaximin treatment.

I have to say that this reminds me of using L-Reuteri probiotic bacteria to send a signal via the same vagus nerve to release oxytocin in the brain. Seems a better approach than intranasal oxytocin.

I think the study showing Rifaximin improves the response to social stress fits with Dr Goldstein’s use of intranasal TRH to “retune” the brain in the conditions he studied and the potential use to reduce suicide initiations. It is enough for me to see TRH as a possible common factor.

I think Goldstein and the US DoD scientists should have used the TRH super-agonist Taltirelin/Ceredist. It is 30x more potent and yet does not affect thyroid function. It also has a far longer half-life. The other alternative, we now see, would have been to use Rifaximin.

Goldstein has passed away and the US DoD gave upon TRH. Research indicates that intranasal esketamine can rapidly reduce suicidal thoughts. Esketamine was FDA approved in 2019.

Taltirelin was approved for use in humans in Japan in 2000 for spinocerebellar degeneration (SCD).

Note that spinocerebellar degeneration (SCD) has no drug therapy in the US/Europe, even though one has existed in Japan for 25 years. Looks pretty odd to me. In a perfect world low dose Taltirelin could be a useful add-on therapy for many neurological conditions and potentially even for prostatitis! Don’t hold your breath.

Taltirelin is now being researched in animal models of Parkinson’s and fatigue syndromes.

Unless you live in Japan and have a pal who is a doctor, I think autism parents are best off with Rifaximin.

As Maja just pointed out “Rifaximin is still very helpful. I repeat a ten-day course (2x400 mg) every two to three months”, in her adult daughter. We can never know for sure if increased TRH is mechanism, or reduced SIBO, or increased butyric acid, or something else. If it works, stay with it!

The Autonomic Nervous System (ANS), Heart Rate Variability (HRV), Performance Anxiety, Propranolol, Vagus Nerve Stimulation and Autism

Performance anxiety symptoms may include:

·       Racing pulse and rapid breathing.

·       Dry mouth and tight throat.

·       Trembling hands, lips, and voice.

·       Sweaty and cold hands.

·       Nausea 

·       Vision changes.

Today’s post started out to be all about Propranolol, a very old and widely prescribed drug that lowers your blood pressure, but does other interesting things as well. It is used to treat several psychiatric disorders and has been widely trialled in autism. As I started researching I decided to broaden the post to bring in Heart Rate Variability (HRV), which one reader of this blog suggested as a useful measure of the effect of supplements.   HRV is actually a good indicator of a dysfunction in the Autonomic Nervous System (ANS). 

The Autonomic Nervous System (ANS) is a control system that acts largely unconsciously and regulates bodily functions such as the heart rate, digestion, respiratory rate, pupillary response and urination.

Within the brain, the autonomic nervous system is regulated by the hypothalamus. Autonomic functions include control of respiration, cardiac regulation, vasomotor activity (actions upon a blood vessel which alter its diameter) and certain reflex actions such as coughing, sneezing, swallowing and vomiting.

Dysfunctions in the Autonomic Nervous System (ANS) are known to be a common feature of autism.  Propranolol is known to affect the Autonomic Nervous System (ANS) and has been shown in numerous trials and case studies to improve some cases of autism.

Performance anxiety is a well-known off-label use of Propranolol.

Vagus Nerve Stimulation (VNS) is known to affect the Autonomic Nervous System (ANS) and is sometimes used to treat performance anxiety.

Vagus nerve stimulation (VNS) using an implanted device can have profound benefits in severe epilepsy. Less invasive VNS can be achieved transcutaneously and in particular via a branch of the vagus nerve that extends to your ear.

The vagus nerve has many roles including sending inflammatory signalling from the gut to the brain. We saw how this was proved, at least in mice, by severing the vagus nerve. Stimulating the vagus nerve can have significant anti-inflammatory effects, which is why it is being developed to treat a wide range of conditions ranging from arthritis to COPD (severe asthma).

We also saw in a post last year that drinking sodium/potassium bicarbonate has an effect that is very similar to VNS, in that it tamps down your immune system in a very similar way.

The Propranalol Autism Research

Fortunately, in 2018 a review of all Propranolol-related autism research was published. I found this out after having started to trawl through the old research.  The issue of Heart Rate Variability (HRV) as potential marker for propranolol responders that I focused in on, was also picked up in the review paper.

We can start with review paper, which happens to be from England, which still has not fully recovered from the Wakefield saga.  There is a real stigma about treating autism, better call it encephalopathy and treat that!

Propranolol for treating emotional, behavioural, autonomic dysregulation in children and adolescents with autism spectrum disorders

To date, there is no single medication prescribed to alleviate all the core symptoms of Autism Spectrum Disorder (ASD; National Institute of Health and Care Excellence, 2016). Both serotonin reuptake inhibitors and drugs for psychosis possess therapeutic drawbacks when managing anxiety and aggression in ASD. This review sought to appraise the use of propranolol as a pharmacological alternative when managing emotional, behavioural and autonomic dysregulation (EBAD) and other symptoms.

This review indicates that propranolol holds promise for EBAD and cognitive performance in ASD. Given the lack of good quality clinical trials, randomised controlled trials are warranted to explore the efficacy of propranolol in managing EBAD in ASD.

Discussion 

From the 16 articles identified, propranolol dosages ranged from 7.5 mg to 360 mg per day across a range of patients. All studies had a range of outcome measures for those diagnosed with ASD, including a focus on cognitive enhancement, management of social behaviours, EBAD, SIBs, and aggression.

Summary of evidence

Across multiple domains, propranolol had significant benefits in the treatment of adults and children diagnosed with ASD. Propranolol improved cognitive performance, with individuals with ASD demonstrating an improvement in verbal problem solving (Beversdorf et al., 2008; Zamzow et al., 2017), semantic processing (Beversdorf et al., 2011) and working memory (Bodner et al., 2012). No changes in cognitive performance for individuals without ASD were reported (Beversdorf et al., 2008, 2011). Additionally, propranolol exhibited greater functional connectivity in individuals with ASD (Hegarty et al., 2017; Narayanan et al., 2010). Not only does this provide evidence for the ability of propranolol to improve functional connectivity in those with ASD, but also that central and peripheral blockade is more effective than just peripheral blockade as seen by nadolol (Hegarty et al., 2017). It is important to note that a non-significant difference for functional connectivity between placebo and propranolol conditions can be attributed to other hemodynamic factors, such as differences in blood pressure, confounding the effects on blood-oxygen-level-dependent responses during fMRI sessions (Narayanan et al., 2010). Moreover, propranolol decreased functional connectivity in various subnetworks where high baseline functional connectivity was observed. Conversely, for those with low baseline functional connectivity, functional connectivity in these subnetworks increased after the introduction of propranolol, irrespective of diagnostic group (Hegarty et al., 2017). These differences suggest that propranolol, and other beta-adrenergic antagonists may have a greater role in maintaining appropriate patterns of functional connectivity, allowing for more efficient integration of functional networks (Hegarty et al., 2017). These findings also highlight the potential for propranolol to support cognitive processing. Indeed, by modulating noradrenaline, greater associative processing and integration of subnetworks may be achieved. Subsequently, potential improvements in attention-shifting, sensory processing, language communication, and the processing of social information could be observed in those with ASD (Hegarty et al., 2017). Furthermore, propranolol reduced mouth fixation, improving facial scanning at a global level (Zamzow et al., 2014). Although, non-significant findings were reported when investigating the efficacy of single-dose propranolol treatment for eye contact, this may be attributable to the sample used. The majority of subjects fulfilling diagnostic criteria for ASD were high functioning, suggesting that scores for eye contact may have already been at a ceiling prior to the administration of propranolol. Therefore, none or only marginal improvements would be attained from post administration of propranolol leading to non-significant results when compared with controls. Moreover, non-verbal communication improvements (Zamzow et al., 2016) and reductions in hypersexual behaviours (Agrawal, 2014) were also observed. These improvements were reported in studies using a 40 mg dose of propranolol, with just one study utilising a low dose of 20 mg (Agrawal, 2014). However, it may be noteworthy to consider that for this case, the hypersexual behaviours did not decrease while the patient was alone, but the patient was able to manage behaviours more appropriately in the presence of others. This may indicate an improved ability to understand and interpret social contexts, rather than a reduction in hypersexual behaviours. Indeed, social cues and social situations are a challenge for those with ASD, and these findings highlight potential clinical implications for propranolol. In light of this, both studies by Sagar-Ouriaghli et al. (2017) and Santosh et al. (2017) highlight again that on average, a 40 mg dose is suitable for children and adolescents in managing symptoms associated with ASD and EBAD. Furthermore, Santosh et al. (2017) and Zamzow et al. (2017) provide supporting evidence for the use of wearable technologies in measuring biomarkers such as HRV and skin conductance in order to identify treatment responders and monitoring the impact of propranolol on therapeutic outcomes. Alongside these benefits, propranolol significantly helped manage SIBs and aggressive outbursts in those with ASD (Knabe and Bovier, 1992; Lyskowski et al., 2009; Ratey et al., 1987). Two cases reported no significant improvement when using propranolol (Connor, 1994; Luiselli et al., 2000). One case was required to change propranolol due to hypotension and bradycardia despite a decreasing trend in aggressive behaviours (Luiselli et al., 2000). Across these cases, dosing ranged from 7.5 mg–360 mg, indicating a higher dose may be required for SIBs and aggression, in comparison with cognitive performance (20 mg–40 mg). In summary, these results and a subsequent overview by Fleminger et al. (2006) conclude that β-blockers have the best evidence for the management of such symptoms and that propranolol improves impulse control and subsequent violence associated with brain dysfunction of diverse aetiologies.

You can read the original 16 studies referred to if you are seriously interested in Propranolol. I have just highlighted some I found interesting.  It is interesting that beneficial effects are reported across the spectrum from severe autism to Asperger’s. 

Successful Management of Difficult-to-Treat Aggression With Low-Dose Propranolol in a Patient With Intellectual Disability: A Case Report

People with intellectual disability often exhibit various behavioral problems, which are referred to as “challenging behaviors.” Aggression is among the commonest of these, affecting about 7% of this population. The management of aggression in these patients involves both behavior therapy and medications. Various medications, such as lithium, anticonvulsants, and antipsychotics, have been used, but their evidence base is limited and recent research suggests that antipsychotics, in particular, should not be routinely used. 

Propranolol is a centrally acting β-adrenergic antagonist used in a variety of medical conditions. It has also been used to manage aggression in various neuropsychiatric conditions, including organic brain syndromes, schizophrenia, dementia, and intellectual disability. Doses used in these studies have been as high as 520 mg/d, but some authors have reported benefits at much lower doses. The following is the case of a young man with intellectual disability, epilepsy, and severe aggression who responded remarkably to low-dose propranolol.

Case report. Mr A, a 20-year-old man diagnosed as having moderate intellectual disability and generalized epilepsy, presented to our clinic with severe aggression, both verbal and physical, occurring with little or no provocation over the past 3 years. These episodes would last up to several hours and often led to food refusal. Before this, he could attend to his personal needs, helped his mother in household tasks, and could communicate in short sentences despite an articulation defect. However, after the onset of his aggression, it was difficult to engage him in any activities, including basic self-care. There was no evidence of a mood disorder or psychosis or of seizures either preceding or following the episodes of aggression. He was seizure-free for the past 4 years on carbamazepine 1,000 mg/d and diazepam 10 mg/d, and he had never exhibited postictal aggression in the past. He had already received trials of olanzapine (up to 15 mg/d for 6 weeks) and chlorpromazine (up to 400 mg/d for 3 months) without significant improvement and was currently on olanzapine 10 mg/d and chlorpromazine 300 mg/d in addition to his medications for epilepsy.

As his mother reported features of autonomic arousal—such as increased perspiration, motor agitation, and rapid breathing—during each episode, he was given a trial of propranolol, starting at 20 mg/d and increased by 20 mg every week. At 40 mg/d, there was a significant reduction in his aggression, and his food intake was better. On further increasing the dose to 60 mg/d, his mother reported that he was essentially “normal,” with no significant episodes of aggression. Over the next year, olanzapine and chlorpromazine were tapered and stopped, and he remained stable. He has been well on carbamazepine 1,000 mg/d, propranolol 60 mg/d, and diazepam 10 mg/d for the past 3 months with no recurrence of either seizures or aggression, and it is now possible to engage him in household tasks and speech therapy.

The management of aggression in the intellectually disabled is a clinical challenge. The best evidence suggests that antipsychotics are of limited use, and the evidence for other medications is even more limited. Behavioral management is valuable, but may not be feasible in a very violent or uncooperative patient, and pharmacotherapy may be required initially in such cases.

Propranolol is effective in reducing aggression in a variety of neurologic and psychiatric conditions. Its exact mechanism of action is unknown, but may involve central β-adrenergic blockade, peripheral effects on the sympathetic nervous system, or serotonergic blockade. It may be effective not only in aggression, but also in the self-injurious behavior commonly seen in the intellectually disabled. Recent evidence suggests that it may improve some aspects of learning in patients with autism. Given these properties, and the uncertainties surrounding other treatment options, low-dose propranolol may be a valuable treatment option in the management of aggression in intellectually disabled adults, even if they do not respond to other drugs.

Amelioration of Aggression and Echolalia With Propranolol in Autism Spectrum Disorder

Conclusions

Although the autonomic hyperactivity hypothesis of aggression in ASD partially explains the behavior of our patient, aggression likely stems from multiple sources beyond just peripheral autonomic arousal. The rapid improvement with propranolol at a fairly low dose suggests that a subpopulation of patients may benefit from non-selective beta blockers. As beta blockers have hemodynamic side effects that include hypotension and bradycardia, clinicians should record baseline vitals and monitor for orthostasis, dizziness, and syncope. Overall, beta blockers may serve as an important therapy for aggression but should not replace a multimodal interventional plan that encompasses pharmacology, psychotherapy, and social support. It will be beneficial to validate the utility of propranolol and other beta blockers for ASD in future randomized controlled trials.

·       Though autism spectrum disorder (ASD) is primarily a disorder of language and social functioning, there may also be significant autonomic dysfunction that could contribute to aggression and impulsivity often seen in the disorder.

·       Beta-adrenergic blocking agents have been shown to reduce aggression in patients with traumatic brain injury and adult-onset neuropsychiatric disorders, but evidence is still limited in patients with ASD.

·       The non-selective beta-blockers propranolol and nadolol may significantly alleviate aggression, echolalia, and vital sign derangements in autistic patients; it is unknown whether β1-selective antagonists would have similar effects.

Here we have the effect on high functioning autism:-

Effect of propranolol on word fluency in autism.

OBJECTIVE AND BACKGROUND:

Autism is characterized by repetitive behaviors and impaired socialization and communication. Preliminary evidence showed possible language benefits in autism from the β-adrenergic antagonist propranolol. Earlier studies in other populations suggested propranolol might benefit performance on tasks involving a search of semantic and associative networks under certain conditions. Therefore, we wished to determine whether this benefit of propranolol includes an effect on semantic fluency in autism.

METHODS:

A sample of 14 high-functioning adolescent and adult participants with autism and 14 matched controls were given letter and category word fluency tasks on 2 separate testing sessions; 1 test was given 60 minutes after the administration of 40 mg propranolol orally, and 1 test was given after placebo, administered in a double-blinded, counterbalanced manner.

RESULTS:

Participants with autism were significantly impaired compared with controls on both fluency tasks. Propranolol significantly improved performance on category fluency, but not letter fluency among autism participants. No drug effect was observed among controls. Expected drug effects on heart rate and blood pressure were observed in both the groups.

CONCLUSIONS:

Results are consistent with a selective beneficial effect of propranolol on flexibility of access to semantic and associative networks in autism, with no observed effect on phonological networks. Further study will be necessary to understand potential clinical implications of this finding.

This paper is interesting because it looks at how you can identify people who are likely to respond to Propranolol:-

Alterations in autonomic nervous system in autism spectrum disorders: Means of detection and intervention

Autism spectrum disorders are a group of developmental disorders, which display significant heterogeneity of symptoms. Besides the core symptoms, various comorbidities are common for individuals with autism. A growing body of evidence suggests dysfunction of autonomic nervous system within the ASD population. The detection of autonomic abnormalities could help in more personalized approach, which takes into account individual etiologic differences. It has also been suggested that interventions focused on autonomic function could possibly be beneficial for treatment of aggression, anxiety, as well as the core symptoms of autism.

Detection of autonomic alterations in autism spectrum disorders

Invasive methods 

The measurement of circulating catecholamines belongs to most common methods of assessment of sympathetic nervous system function (SNS) (Zygmunt & Stanczyk 2010). Activity of the SNS can be assessed using the measurement of the plasma or urine concentration of norepinephrine, or its metabolites. Measurement of catecholamines provides useful information about the activity of SNS, however, they are determined by location of vessel used for blood collection and therefore do not reflect the whole amount of neurotransmitter secreted from axon terminal (Sinski et al 2006). Acetylcholine, neurotransmitter released by postganglionic fibers of the parasympathetic system, is very quickly inactivated by acetylcholinesterase, so its plasma levels cannot be used as a marker of parasympathetic nervous system activity (McCorry 2007). Interestingly, plasma norepinephrine concentrations have been reported to be elevated in autism (Launay et al 1987). However, blood and urine samples acquisition represent extremely stressful stimuli for children with autism spectrum disorders and thus pose a challenge for researchers in obtaining such samples from both ethical and methodological reasons. Therefore, various non-invasive methods of ANS activity detection have been developed. 

Non-invasive methods 

To assess autonomic nervous system activity, various non-invasive methods are used. For example, measurement of sympathetic skin response is used frequently (Claus & Schondorf 1999, Kucera et al 2004). This method is based on determination of the alterations in skin electrical resistance in response to activation of sweat glands which are stimulated by impulses conducted by cholinergic postganglionic sympathetic fibers. However, it is important to note, that in general, skin conductance level are not stable and therefore it is difficult to define baseline values and there are large intra- and inter-individual differences (Boucsein et al 2012). Another widely used method has become pupillometry, biomarker of LC-NE system. Several studies found both dysregulated tonic pupil responses to various stimuli (e.g. Anderson et al 2006, Martineau et al 2011) and greater skin conductance level (Prince et al 2016) in children with ASD. One of the most reliable methods for measurement of ANS activity, namely cardiac autonomic responses, has become heart rate variability (HRV). HRV refers to beat-to-beat variations of the heart rate that is determined by autonomic nervous system. In resting conditions, the variability of beat-to-beat intervals remains large and becomes more regular when influenced by stressful environmental factors (Task force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology 1996). Because of the fast degradation of acetylcholine by acetylcholinesterase, the influence of parasympathetic activation is quick and thus accounts for fast changes in heart rate. Sympathetic influence changes more slowly, its effect is observable as a change in heart rate after longer period, and thus is responsible for slower oscillations. HRV has been found to be decreased in autism spectrum disorders in number of studies (Daluwatte et al 2013, Ming et al 2005). These data

Interventions affecting vagal activity for adjuvant treatment of children with ASD 

In the light of above mentioned findings, several new treatment options are now being explored. Vagus nerve stimulation, which involves surgical implantation of electrodes around cervical portion of the vagus nerve, was found to increase HRV. Study of Hull et al (2015) showed decreased severity and duration of seizures in children with refractory epilepsy and autism after stimulation of vagus nerve. Moreover, they found the improvement in ASD symptoms not related to epilepsy, such as communication skills, or stereotyped behavior. Furthermore, considerable improvement in regulation of aggressive behavior and receptive communication skills were noted and maintained over 1 year. The biggest drawback of vagus nerve stimulation method is cost and requirement of invasive neurosurgery. However, recent studies confirmed the possibility of noninvasive transcutaneous stimulation of the vagus nerve with electrodes located in the auricular concha area that is densely innervated by branches of the vagus nerve (Fang et al 2016). Electrical stimulation of the cervical vagus nerve with handheld device represent another non-invasive method (Schoenen et al 2016). In preterm infants or high-risk infants, kangaroo care or massage therapy may increase vagal tone and promote optimal neurodevelopment (Feldman & Eidelman 2003). Similar preliminary data were obtained on children with ASD, as well (Escalona et al 2001).

This new clinical trial looks very interesting because it includes looking at predictors for responders:-

Trial of Propranolol in Children and Youth With Autism Spectrum Disorder and Predictors of Response

The specific aim of this study is to examine the effects of serial doses of propranolol on social interaction, and secondarily on language tasks, anxiety, adaptive behaviors, and global function in high functioning adults and adolescents with autism in a double-blinded, placebo-controlled trial. The investigators will also examine whether response to treatment can be predicted based upon markers of autonomic functioning, such as skin conductance, heart rate variability (HRV), and the pupillary light reflex (PLR), and whether anxiety can predict treatment response. The hypothesis is that social functioning and language abilities will benefit from serial doses of propranolol, and that those with the greatest degree of autonomic dysregulation, or the lowest functional connectivity, will demonstrate the greatest benefit from the drug.

Propanolol will be given on a titration schedule in which participants will begin with small doses (single capsules) of the drug and increase to a larger dosage (divided over 3 capsules) over the course of three weeks. Participants aged 15-24 years will undergo an MRI.

 Autonomic Dysfunction in Autism

Autonomic Dysfunction in Autism Spectrum Disorders  (ASD) 

Abstract

Objective: To report a case series of clinically significant autonomic dysunction in ASD. 

Background:Autonomic nervous system (ANS) impairment has been increasingly recognized in autism spectrum disorders (ASD). Abnormalities in pupillary light reflex, resting heart rate, heart rate response to social cognitive tasks, respiratory rhythm, and skin conductance suggest that autonomic dysfunction is common in ASD and may play a role in the social, behavioral, and communication problems that are the hallmark of this neurodevelopmental disorder. This case series confirms the presence of clinically significant multisystem ANS dysfunction in ASD. 

Methods: Patients with a history of ASD who underwent an evaluation for ANS dysfunction at our institution were identified. Clinical features, findings on autonomic testing, and laboratory results were reviewed.

Results: Six patients with ASD underwent clinical and autonomic evaluation, ranging in age from 12 to 28, and autonomic symptom duration ranging from 10 months to 6 years. All reported postural lightheadedness, near-syncope, and rapid heart rate. Five reported significant gastrointestinal (GI) symptoms including constipation, diarrhea, and early satiety. Autonomic testing revealed an excessive postural tachycardia with head-up tilt (HUT) in all patients, with a mean heart rate (HR) increment of 50 bpm, mean maximum HR on HUT of 118 bpm, absence of orthostatic hypotension on HUT. Abnormal blood pressure profile with the Valsalva maneuver was identified in three patients. All five patients were diagnosed with orthostatic intolerance. Supine norepinephrine (NE) was low in three of the four patients tested and an inadequate rise in standing NE was noted in two of these patients. GI motility testing was performed in two patients, and suggested gastroparesis in one patient.

Conclusions: Clinically significant ANS dysfunction may occur in ASD, with symptoms suggestive of orthostatic intolerance and gastrointestinal dysmotility, and findings on autonomic testing demonstrating an excessive postural tachycardia.

Functional autonomic nervous system profile in children with autism spectrum disorder

         
           Background

Autonomic dysregulation has been recently reported as a feature of autism spectrum disorder (ASD). However, the nature of autonomic atypicalities in ASD remain largely unknown. The goal of this study was to characterize the cardiac autonomic profile of children with ASD across four domains affected in ASD (anxiety, attention, response inhibition, and social cognition), and suggested to be affected by autonomic dysregulation.

Methods

We compared measures of autonomic cardiac regulation in typically developing children (n = 34) and those with ASD (n = 40) as the children performed tasks eliciting anxiety, attention, response inhibition, and social cognition. Heart rate was used to quantify overall autonomic arousal, and respiratory sinus arrhythmia (RSA) was used as an index of vagal influences. Associations between atypical autonomic findings and intellectual functioning (Weschler scale), ASD symptomatology (Social Communication Questionnaire score), and co-morbid anxiety (Revised Children’s Anxiety and Depression Scale) were also investigated.

Results

The ASD group had marginally elevated basal heart rate, and showed decreased heart rate reactivity to social anxiety and increased RSA reactivity to the social cognition task. In this group, heart rate reactivity to the social anxiety task was positively correlated with IQ and task performance, and negatively correlated with generalized anxiety. RSA reactivity in the social cognition task was positively correlated with IQ.

Conclusions

Our data suggest overall autonomic hyperarousal in ASD and selective atypical reactivity to social tasks.

The Vagus nerve as a means to affect the ANS 

Vagal Nerve Stimulation in Autonomic Dysfunction – A Case Study

Background: Autonomic nervous system function is influenced by the balance of the parasympathetic and sympathetic systems. Management for imbalance of these components causing dysfunction is largely focused on medications primarily improving cardiovascular tone. However, there appears to be an opportunity for therapy by modulating neurotransmission. Methods: Our patient is a nine year old female with history of intractable epilepsy and developmental delay related to confirmed genetic abnormalities and also complaints of episodic pallor, fatigue, light-headedness and headaches concerning for dysautonomia. Results: Our patient underwent vagal nerve stimulator (VNS) implantation for treatment of epilepsy and showed improvement of these symptoms at typical settings. Headup tilt test (HUTT) was subsequently performed and revealed normal findings and no subjective symptoms of autonomic dysfunction. A repeat HUTT was performed five months later with VNS output currents set to zero and revealed cardiovascular changes and clinical symptoms consistent with dysautonomia. With resumption of previous VNS settings, clinical symptoms resolved.

Conclusions: Neurotransmission from vagal afferents to brainstem nuclei is increased during VNS affecting multiple brainstem areas and the cerebral cortex, including regions controlling autonomic function. Studies have suggested a role for VNS in patients with clinical signs of autonomic dysfunction showing improvement in sympathovagal balance after VNS implantation. In our patient, we observed subjective and objective improvement in autonomic function. This initial case demonstrates a phenomenon that requires further study, may lead to improved understanding of autonomic function and the response to vagal nerve stimulation, and possibly a new indication for VNS therapy.

Mechanisms underpinning sympathetic nervous activity and its modulation using transcutaneous vagus nerve stimulation

The autonomic nervous system, consisting of the sympathetic and parasympathetic branches, is a major contributor to the maintenance of cardiovascular variables within homeostatic limits. As we age or in certain pathological conditions, the balance between the two branches changes such that sympathetic activity is more dominant, and this change in dominance is negatively correlated with prognosis in conditions such as heart failure. We have shown that non-invasive stimulation of the tragus of the ear increases parasympathetic activity and reduces sympathetic activity and that the extent of this effect is correlated with the baseline cardiovascular parameters of different subjects. The effects could be attributable to activation of the afferent branch of the vagus and, potentially, other sensory nerves in that region. This indicates that tragus stimulation may be a viable treatment in disorders where autonomic activity to the heart is compromised.

The Vagus Nerve as a target to reduce inflammation

Regardless of its effects on the autonomic nervous system (ANS), we know from the research in earlier blog posts that vagus nerve stimulation can significantly reduce inflammation.  Here is an easy to read article as a reminder.

Vagus Nerve Stimulation Dramatically Reduces Inflammation

Stimulating the vagus nerve reduces inflammation and the symptoms of arthritis.

Healthy vagal tone is indicated by a slight increase of heart rate when you inhale, and a decrease of heart rate when you exhale. Deep diaphragmatic breathing—with a long, slow exhale—is key to stimulating the vagus nerve and slowing heart rate and blood pressure, especially in times of performance anxiety.

A higher vagal tone index is linked to physical and psychological well-being. Conversely, a low vagal tone index is associated with inflammation, depression, negative moods, loneliness, heart attacks, and stroke.

There are many ways put forward to  stimulate the vagus nerve simply without electrical devices. Here is one list I came across:-

1.     Slow deep breathing. An example would be to breathe in slowly for a count of 4 and out for a count 6 to 8. The average normal breathing rate is between 12 and 14 per minute. This slow breathing reduces it to 6 to 7 per minute.

2.     Any exposure to cold. eg rinse your hands and face in cold water.

3.     Singing, chanting, gargling and humming

4.     Laughter

5.     Restorative yoga postures such as the cat cow posture and downward dog

6.     Meditation.

7.     Evoking the emotions of love, compassion and empathy.

8.     Exercise

9.     Massage/acupuncture, acupressure

10. Intermittent fasting

I found re-reading this old post interesting

Drinking Baking Soda for Vagal Nerve Stimulation?

It prompted me to order some potassium bicarbonate.

Conclusion

I think when you read about what the Autonomic Nervous System (ANS) does in your body you are likely to be able to judge whether or not it may be dysfunction. Hopefully the research will identify reliable markers, whether it is heart rate variability (HRV) or pupillary light reflex (PLR).

I do not think Autonomic Nervous System (ANS) dysfunction is a cause of autism, but it may be a consequence of it. Correcting any such dysfunction may have an impact ranging from trivial to profound.

I know that some readers of this blog have been using Propranolol for some time already. It has been very well researched, by the standards of autism. Being a cheap generic drug, there is little interest to spend $8 million in Europe to have it approved for autism, or the $20 million needed in the US. 

It should be noted that while Propranolol is a very widely used drug it does have side effects and interactions. Some other autism drugs used off-label do reduce blood pressure.

Propranolol is a competitive antagonist of beta-1-adrenergic receptors in the heart. It competes with sympathomimetic neurotransmitters for binding to receptors, which inhibits sympathetic stimulation of the heart. Blockage of neurotransmitter binding to beta 1 receptors on cardiac myocytes inhibits activation of adenylate cyclase, which in turn inhibits cAMP synthesis leading to reduced PKA production. This results in less calcium influx to cardiac myocytes through voltage gated L-type calcium channels meaning there is a decreased sympathetic effect on cardiac cells, resulting in antihypertensive effects including reduced heart rate and lower arterial blood pressure.

One side effect of Propranolol is low heart rate (bradycardia), but some people do have too high a heart rate.

Propranolol is a so-called negative inotropic agent, meaning it reduces the strength of contractions of heart muscle. This is why it reduces blood pressure.

Negative inotropic effects can be additive, which means not surprisingly if you take another negative inotropic agent, like an L-type calcium channel blocker, you have to be careful.

There are medical conditions for which the combined use of Propranolol and Verapamil has been suggested, but at the high doses often used this looks rather unwise.

There are interactions between Propranolol and many drugs; note that Verapamil will raise the serum level of propranolol.

The good news is that the dosage often effective in autism is quite low.

The adult dose for Migraine Prophylaxis is up to 240mg a day.  Some of the regular pediatric doses are also huge, compared to the “autism dosage” which can be 40mg of even less.

The initial paper we looked at in this post, from ultra-sceptical that autism can be treated England, concluded:

 “… randomised controlled trials are warranted to explore the efficacy of propranolol in managing EBAD (emotional, behavioural and autonomic dysregulation) in ASD”

Are severe headaches that occur in some autism another possible predictor of Propranolol responders?

Is stuttering another symptom to look out for?

Autonomic nervous system activity of preschool-age children who stutter