Showing posts with label propranolol. Show all posts
Showing posts with label propranolol. Show all posts

Wednesday 30 November 2022

Repurposing Anti-parasite drugs to treat Cancer and Autism?


I should start this post by highlighting that generally cancer and autism are not caused by parasites.

I have to be a little careful because we now know that certain types of virus and bacteria are involved in the initial trigger to initiate some types of cancer. This is why many females are now offered human papillomavirus (HPV) vaccines to minimize the chance of several different cancers. I noticed recently that in the US this vaccine is advertised on TV.  I used to know a woman who like most people had the HPV virus as a child, but did not have this vaccine.  She developed a rare oral cancer that the vaccine would have protected against and died very young. We saw in a previous post how a specific gut bacteria blocks the initiation of childhood leukemia.

The pharmaceutical industry does not seem to like the idea of repurposing existing drugs to treat a different disease.  There are some exceptions; it is OK to treat females with acne, using the diuretic drug Spironolactone.  Nobody seems to object to the treatment of intractable headaches with drugs actually approved to lower blood pressure (Verapamil, Amlodipine etc).

When investigating cancers you have to look at the specific underlying mechanisms, just as you do with autism.

As we saw long ago in this blog, it has been suggested to classify autism as either over-active pro-growth signaling pathways, or under-active pro-growth signaling pathways. Most is the over-active type.

Cancer is very clearly another example of over-active pro-growth signaling pathways, so it is not surprising that there is an overlap between therapies for autism and cancer.  The difference is that they are far more likely to be effective in autism. 

So, a cheap anti-parasite drug for kids like Mebendazole, which just happens to also be a Wnt inhibitor,  may slow down the growth of some cancers, but it is sadly not curative.  In an autistic brain where Wnt signalling might be overactive, a lower dose of Mebendazole, might well provide a long-term benefit.   

My old posts that mention Wnt signaling are here:- 

Wnt signaling interestingly plays a role in how your hair will go gray/grey. If you reduce Wnt signaling, your hair will go gray and so this is an inevitable side effect of a potent Wnt inhibitor. 

Premature graying might indeed indicate reduced Wnt activity.


Pyrantel pamoate

Our reader Dragos recently fined tuned his adult son’s anti-aggression therapy and he recently shared his latest innovation:-


"you have to give him 20mg of propranolol 2-3 times a day, pyrantel pamoate 750mg in the evening for 2-3 days, and you will see that his anger will disappear, stay on propranolol. After 3 weeks repeat with antiparasitic, you will see that I was right, you don't use psychotropic drugs"


Propranolol is a normally used to lower blood pressure, but it does this in a way that also reduces anxiety.  At the low doses used by Dragos, it has been used to treat actors with stage fright. It can be used before exams or driving tests, to calm the person down.

Propranolol has been trialed in autism. Some people use a low dose and some use a higher dose.

Pyrantel pamoate is used to treat hookworms and other parasites that can be picked up by young children. It works by paralyzing the worms. This is achieved by blocking certain acetylcholine receptors in the worm.

As is very often the case, pyrantel pamoate likely has other modes of action that are entirely different. Is it a Wnt inhibitor like the other hookworm treatment Mebendazole?

I did a  quick search on google and it gave me the wrong pamoate. 

Pyrvinium pamoate is able to kill various cancer cells, especially CSC. The drug functions through the reduction of WNT- and Hedgehog-dependent signaling pathways (Dattilo et al., 2020). 

Pyrvinium pamoate is yet another anti-parasitic drug, but not the one Dragos is using.

So pyrantel pamoate may not be a Wnt inhibitor, unlike many anthelmintic drugs, but it is used by the “anti-parasitic re-purposer in chief” Dr Simon Wu.  He publishes his findings/thoughts, which is good to see.  He likes to combine different anti-parasitic drugs.

I did look up the effect of pyrantel pamoate on gene expression.  There is data, but you really need to see the source material to know whether anything is valid.

Inhibiting GSTP1 (glutathione S-transferase pi 1) is suggested and that is a feature in common with an anti-parasite drug class called Thiazolides (e.g.  Nitazoxanide).  That would make pyrantel pamoate a potential therapy for triple-negative breast cancer, where the cancer cells rely on vigorous activity by the enzyme glutathione-S-transferase Pi1 (GSTP1).  Cancer cells are highly vulnerable to oxidative stress, and as we know glutathione is the main way the body extinguishes it. Glutathione S-transferases P1 protects breast cancer cell from cell death.  So you want to inhibit GSTP1.

Pyrantel has many other suggested effects even reducing expression of the gene FXR2 (fragile X mental retardation,2) and increasing expression of the gene MTSS1 (metastasis suppressor 1).

Pyrantel is even suggested as an epilepsy drug.


Drug repositioning in epilepsy reveals novel antiseizure candidates

Epilepsy treatment falls short in ~30% of cases. A better understanding of epilepsy pathophysiology can guide rational drug development in this difficult to treat condition. We tested a low-cost, drug-repositioning strategy to identify candidate epilepsy drugs that are already FDA-approved and might be immediately tested in epilepsy patients who require new therapies.

Expanding on these analyses of epilepsy gene expression signatures, this study generated a list of 184 candidate anti-epilepsy compounds. This list of possible seizure suppressing compounds includes 129 drugs that have been previously studied in some model of seizures and 55 that have never been studied in the context of seizures. 91 of these 184 compounds are already FDA approved for human use, but not for treating seizures or epilepsy. We selected four of these drugs (doxycycline, metformin, nifedipine, and pyrantel tartrate) to test for seizure suppression in vivo.

Pyrantel tartrate is an antiparasitic agent that acts by inhibiting fumarate reductase, and by directly acting on acetylcholine receptors at the neuromuscular junction of infecting helminths. Pyrantel tartrate is FDA approved for use in domestic animals and has been used to treat human parasitic infections.73 Unlike nifedipine and metformin (for which some rodent studies and human reports relate to seizures), a March 2018 PubMed search for “pyrantel and epilepsy” and “pyrantel and seizure” found no manuscripts that studied pyrantel in seizures. Thus, pyrantel tartrate represents a truly novel antiseizure drug candidate yielded by our screen.


All in all it is not surprising that Dr Yu is prescribing pyrantel pamoate.

Digging any deeper is beyond the scope of a blog post.

What is clear is that pyrantel pamoate and mebendazole are unlikely to be equally effective in Dragos’ son.

Other anti-parasite drugs work very differently.

In the chart the mode of action of some common drugs  is presented.


Anthelminticsfor drug repurposing: Opportunities and challenges


Mode of action of albendazole (ABZ), ivermectin (IVM), levamisole (LV), mebendazole (MBZ), niclosamide (NIC), flubendazole (FLU), rafoxanide (RAF), nitazoxanide (NTZ), pyrvinium pamoate (PP), and eprinomectin (EP).


Suramin is now quite well known as a potential autism therapy and two different groups are trying to commercialize it.  Suramin is the original anti-purinergic drug (APD), it blocks purinergic receptors that have names like P2Y2.

When I looked at PAK1 a long time ago, which was put forward as a treatment pathway for neurofibromatosis, some schizophrenia and some autism I came across Ivermectin as an existing alternative to the research drug FRAX486, or the expensive BIO 30 propolis from New Zealand.

A decade later and the world goes crazy when the idea of using Ivermectin to treat COVID 19 gets well publicized.  The good news is that now we know that regular use of Ivermectin is not as dangerous as people thought it would be.  Many people have been using the veterinary version in the US, Brazil and elsewhere. 

The supporting research:- 

Effect of Pyrantel on gene expression.


decreases expression of:-

FXR2   fragile X mental retardation, autosomal homolog 2

(and many more)


Increases expression of

MTSS1 metastasis suppressor 1

BNIP1 BCL2/adenovirus E1B 19kDa interacting protein 1

BRAF B-Raf proto-oncogene, serine/threonine kinase

(and many more)

Glutathione S-transferase P is an enzyme that in humans is encoded by the GSTP1 gene.

Pyrantel Pamoate Gene Set

Dataset          CTD Gene-Chemical Interactions

2 genes/proteins interacting with the chemical Pyrantel Pamoate from the curated CTD Gene-Chemical Interactions dataset.

GPR35    G protein-coupled receptor 35

GSTP1   glutathione S-transferase pi 1


Triple-negative breast cancer target is found

They discovered that cells from triple-negative breast cancer cells rely on vigorous activity by an enzyme called glutathione-S-transferase Pi1 (GSTP1). They showed that in cancer cells, GSTP1 regulates a type of metabolism called glycolysis, and that inhibition of GSTP1 impairs glycolytic metabolism in triple-negative cancer cells, starving them of energy, nutrients and signaling capability. Normal cells do not rely as much on this particular metabolic pathway to obtain usable chemical energy, but cells within many tumors heavily favor glycolysis.


"Inhibiting GSTP1 impairs glycolytic metabolism," Nomura said. "More broadly, this inhibition starves triple-negative breast cancer cells, preventing them from making the macromolecules they need, including the lipids they need to make membranes and the nucleic acids they need to make DNA. It also prevents these cells from making enough ATP, the molecule that is the basic energy fuel for cells." 


Anthelmintics for drug repurposing: Opportunities and challenges 

It has been demonstrated that some of the anthelmintics are able to inhibit critical oncogenic pathways, such as Wnt/β-catenin, signal transducer and activator of transcription proteins 3 (STAT3), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB; therefore, their application for cancer treatment has been considered.


Repositioning of Anthelmintic Drugs for the Treatment of Cancers of the Digestive System


Anthelmintics for drug repurposing: Opportunities and challenges


Mode of action of albendazole (ABZ), ivermectin (IVM), levamisole (LV), mebendazole (MBZ), niclosamide (NIC), flubendazole (FLU), rafoxanide (RAF), nitazoxanide (NTZ), pyrvinium pamoate (PP), and eprinomectin (EP).


Thiazolides inhibit growth and induce glutathione-S-transferase Pi (GSTP1)-dependent cell death in human colon cancer cells

More research on the repurposing anti-parasite drugs: 

Antiparasitic and Antifungal Medications for Targeting Cancer Cells Literature Review and Case Studies Frederick T. Guilford, MD; Simon Yu, MD

Chronic inflammation is a new catch phrase for the explanation of all chronic degenerative diseases, from asthma, arthritis, heart disease, auto-immune disease, and irritable bowel disease to cancer. Occult infections from oncovirus, bacterial, and fungal infections as well as from lesser known parasitic infections are driving forces in the cellular evolution and degeneration of cancer cells. An approach using currently available medications that target both fungal and parasitic metabolism appears to interfere with the metabolic synergy that is associated with tumor growth and aggressiveness 


The Antitumor Potentials of Benzimidazole Anthelmintics as Repurposing Drugs 


Repurposing Drugs in Oncology (ReDO)—mebendazole as an anti-cancer agent 


A Pinworm Medication Is Being Tested As A Potential Anti-Cancer Drug


I did suggest long ago that Mebendazole, as a Wnt inhibitor, might be a cheap and effective treatment for some autism.  I had envisaged that it would need to be given daily, as it is in the cancer trials.

Dragos’ use of pyrantel pamoate, for an average of 4 days a month is interesting.  It is cheap, safe and practical.

One key issue with antiparasitic drugs is how much is absorbed into the blood stream.  If 100% of the drug stays in the gut, its benefit will be limited.

About 20% of Mebendazole ends up in the blood stream and if you take it often this figure is reported to increase.

The combo of propranolol + pyrantel pamoate is an interesting option to treat self-injury and aggressive behavior.  It works for Dragos and undoubtedly will for some others.

Is the inhibition of Wnt signalling the reason why pyrantel pamoate is effective for Dragos’ son?  There is no evidence to support that.

Are antiparasitic drugs going to be widely adopted to treat any unrelated conditions, cancer included, I very much doubt it.

Cancer is better avoided, than treated.  It is a much more achievable objective.

The Fragile X researcher Randi Hagerman takes metformin, as her chemoprevention therapy. She is the medical director of MIND Institute at the University of California, Davis.

You can raise IQ in people with Fragile X by 10-15% using Metformin.  I guess Randi had been reading up on Metformin and came across the anti-cancer effects.

If I had to suggest an anti-parasite drug for Randi to try in Fragile X, I would suggest the PAK inhibitor Ivermectin, made (in)famous by Donald Trump and Jair Bolsonaro during Covid. The research drug FRAX 486 is called FRAX for Fragile X. It is a PAK inhibitor that never made it to market.  Ivermectin is an existing drug that is also a PAK inhibitor.  Worth a try, Randi?

I expect Dr Yu might try and increases his chances and make a combo with a second anti-parasitic drug.

Metformin is one of several anti-cancer choices, it depends which type of cancer is of concern. For RAS-dependent cancer I think Atorvastatin is the best choice. 

If you read the research, like me and Randi, chemoprevention is the obvious choice for older adults. Dementia prevention is equally obvious.

Parkinson’s prevention may be achieved by blocking Cav1.3 (amlodipine etc)

Alzheimer’s prevention may be achieved using low dose fenamates (Ponstan etc).

For vascular dementia and Alzheimer’s prevention/treatment spermidine (in the form of modified wheatgerm) is promising.

Anti-parasite drugs for cancer and autism? Yes, it sounds mad. But is it?

What is for sure is that your pediatrician will think you have gone mad!

Our reader MG in Hong Kong will have got some new ideas to think about.

Friday 26 April 2019

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!

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.

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. 

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


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:-


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.


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.


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.


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:-

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:-

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


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


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.


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.


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.


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.

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.


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?