Clonidine and Guanfacine for ADHD, mast cell activation, sleep disorders, tics and some self-injurious behavior (SIB)

 

Both clonidine and guanfacine were raised recently to me, they have been covered in various earlier posts and in my book. Here is a round-up of the information.

These two drugs are α2A-adrenergic receptor agonists originally used to treat high blood pressure. Subsequently many additional uses of these drugs have been discovered.

I was asked about its use to treat mast cell activation syndrome (MCAS) and the mechanism by which it achieves this effect is interesting.

Calming mast cells – the ones that release histamine during an allergic reaction

Clonidine/guanfacine, as alpha-2 adrenergic agonists, inhibit mast cells primarily by interacting with the central and peripheral nervous systems, leading to a decrease in the release of inflammatory mediators. Its mechanism involves stimulating alpha-2 adrenergic receptors, which in turn suppresses the release of norepinephrine and other neurotransmitters.

In terms of mast cell stabilization, clonidine/guanfacine is thought to reduce intracellular calcium levels and inhibit the degranulation process that releases histamine and other pro-inflammatory substances. Lower intracellular calcium prevents the activation of key signaling pathways that normally trigger mast cell activation and degranulation.

This stabilizing effect helps prevent excessive allergic and inflammatory responses, making clonidine/guanfacine beneficial in conditions where such inhibition is useful.

Clonidine/guanfacine have some calcium channel-blocking properties, though they are not classified as a traditional calcium channel blocker. By indirectly lowering intracellular calcium levels, clonidine/guanfacine inhibit the signaling pathways that lead to mast cell degranulation and the release of inflammatory mediators. The end result is a reduction in cellular excitability and a dampening of the inflammatory response, including mast cell stabilization.

Clearly, you could just go directly to a calcium channel blocker like verapamil.

Clonidine/guanfacine and indeed verapamil are not seen as first line treatments for MCAS but may well be beneficial.

Conventional First-Line Treatments for MCAS

Antihistamines

H1 blockers (e.g., cetirizine, loratadine) to manage allergic-type symptoms like itching, hives, and flushing.

H2 blockers (e.g., famotidine, ranitidine) to control gastrointestinal symptoms and histamine release in the stomach.

Mast Cell Stabilizers

Cromolyn sodium is often considered one of the most effective mast cell stabilizers for MCAS, especially for gastrointestinal symptoms.

Ketotifen, another mast cell stabilizer with antihistamine properties, can also be helpful.

Rupatadine and azelastine are also potentially beneficial as mast cell stabilizers.

Leukotriene Inhibitors

Medications like montelukast can help manage symptoms related to leukotrienes, which are other mediators released by mast cells.

Aspirin

Aspirin can play a role in managing MCAS, particularly in controlling specific symptoms like flushing, hives, and inflammation. Its primary action in MCAS involves inhibiting prostaglandin D2 (PGD2), which is one of the inflammatory mediators released by mast cells and contributes to the vascular symptoms seen in MCAS.

Sleep disorders

Some people with autism do not sleep well.

Clonidine/guanfacine can help some individuals fall asleep faster and stay asleep longer by promoting relaxation and calming overactivity in the brain.

It is sometimes used in pediatric populations, such as children with autism or ADHD, to help with sleep initiation and minimize frequent nighttime awakenings.

Clonidine/guanfacine, being alpha-2 adrenergic agonists, lower the activity of the sympathetic nervous system (the fight-or-flight response).

Clonidine/guanfacine is typically prescribed at a low dose for sleep, as higher doses can lead to daytime drowsiness. Taking clonidine at night, about 30-60 minutes before bed, is common practice.

Guanfacine has a longer half-life than clonidine, which means it provides a more sustained effect throughout the night and may lead to fewer night-time awakenings. This can be particularly useful for individuals who need consistent support for sleep through the night.

Tics

Clonidine/guanfacine have long been used off-label to treat Tourette’s syndrome, which is a tic disorder.

Clonidine/guanfacine can help manage some stereotypical behaviors (repetitive, non-functional behaviors) in individuals with autism, when these behaviors are driven by hyperactivity, impulsivity, or anxiety.

Clonidine/guanfacine helps manage tics by calming the nervous system, modulating norepinephrine release, reducing stress, and helping with impulse control.

This effect has been noted by our reader AW.

Self-injurious behavior (SIB)

Self-injurious behavior (SIB) is usually considered the worst feature of autism. It becomes a learned behavior which can be very hard to extinguish.

Clonidine/guanfacine is on the long list of sometimes effective therapies. Take a note of this!

 

Clonidine as a Treatment of Behavioural Disturbances in Autism Spectrum Disorder: A Systematic Literature Review

Clonidine has a limited evidence base for use in the management of behavioural problems in patients with ASD. Most evidence originates from case reports. Given the paucity of pharmacological options for addressing challenging behaviours in ASD patients, a clonidine trial may be an appropriate and cost-effective pharmaceutical option for this population.

Beneficial Effects of Clonidine on Severe Self-Injurious Behavior in a 9-Year-Old Girl with Pervasive Developmental Disorder

ADHD

ADHD is very commonly diagnosed these days.

The genes involved in ADHD, autism, bipolar and schizophrenia are overlapping, so it is not surprising that many people are now being diagnosed with both ADHD and autism.

What I find very odd is that people with ADHD line up for medical treatment, but most people with comorbid autism think there cannot be a medical treatment for their autism because it is just how their brain is “wired-up differently.” It is hard to reconcile these views - both conditions are clearly treatable.

Most ADHD treatments are stimulants. Medications like methylphenidate (Ritalin, Concerta) and amphetamine-based drugs (Adderall, Vyvanse) are typically considered first-line treatments for ADHD. They work by increasing levels of dopamine and norepinephrine in the brain, which help improve focus, attention, and impulse control in people with ADHD.

Not all individuals with ADHD can tolerate stimulants, and in some cases, they may experience unwanted side effects like anxiety, sleep disturbances, or increased irritability.

The most common non-stimulant options are Clonidine and Guanfacine. They does not directly increase dopamine or norepinephrine but instead reduces norepinephrine release, promoting a calming effect.

Atomoxetine (Strattera) is a selective norepinephrine reuptake inhibitor (NRI), which increases norepinephrine in the brain by blocking its reuptake.

After years of off-label use in by 2010 both clonidine and guanfacine were FDA approved for use in ADHD.

 

Conclusion

As I mentioned to one reader, we should take note that both clonidine and guanfacine are approved for use in children (with ADHD) and so there is plenty of safety information and dosage guidance.

The effective dose for MCAS, sleep disorders, tics and SIB may well vary from person to person but the safe boundaries are well established from ADHD.

In general, guanfacine tends to be better tolerated than clonidine.

AW might note that guanfacine can cause sleep problems, including insomnia or vivid dreams.

Here is a useful list I found:

Common Side Effects:

Sedation/Drowsiness: Like clonidine, guanfacine can cause drowsiness, especially during the initial stages of treatment or when the dose is increased.

Fatigue: Many people report feeling fatigued or tired when starting guanfacine, which can affect daytime functioning.

Low Blood Pressure (Hypotension): Guanfacine also lowers blood pressure, potentially leading to dizziness or light-headedness, particularly when standing up quickly.

Dry Mouth: This is another common side effect, similar to clonidine, and may cause discomfort.

Headache: Some people experience headaches, especially when starting treatment.

Stomach Problems (e.g., abdominal pain, constipation): Gastrointestinal side effects can occur in some individuals, such as constipation or stomach discomfort.

Irritability and Mood Swings: In some cases, guanfacine may cause irritability or emotional instability.

Less Common but Serious Side Effects:

Bradycardia (slow heart rate): As with clonidine, guanfacine can cause a slow heart rate, which could be concerning for individuals with underlying heart issues.

Rebound Hypertension: Discontinuing guanfacine too abruptly can cause rebound hypertension (a sudden increase in blood pressure), so it should be tapered gradually under a healthcare provider’s guidance.

Sleep disturbances: In some cases, though less common than with clonidine, guanfacine can cause sleep problems, including insomnia or vivid dreams.

Cognitive Loss/Impaired Sensory Gating from HCN Channels - Recovered by PDE4 Inhibition or an α2A Receptor Agonist

Today we have a complex dysfunction, but we have a plausible understanding of the detailed biological underpinnings and several therapeutic options. It is relevant to people with autism who have impaired sensory gating (they find noises like a clock ticking annoying), and perhaps those who struggle with complex thought. It is very likely to be disturbed in some people with ADHD and many with schizophrenia.

Trouble in the Pre-Frontal Cortex

For a recap on sensory gating, here is an earlier post:-

Sensory Gating in Autism, Particularly Asperger's

Today’s dysfunction relates to HCN channels located on those tiny dendritic spines in a part of the brain called the pre-frontal cortex. These are a type of voltage gated potassium channel found in your brain and heart, there are 4 types, it looks to me that HCN2 is the key one today.

The pre-frontal cortex (PFC) is seen as the part of the brain most affected by mental illness (schizophrenia, bipolar, ADHD etc.), although medicine’s current understanding looks rather medieval to me.

These HCN channels can open when they are exposed to cAMP (cyclic adenosine monophosphate). When open, the information can no longer flow into the cell, and thus the network (created by numerous interacting neurons) is effectively disconnected.

By keeping these channels closed, it is thought that you can improve working memory and reducing distractibility. Now you might think distractibility is an odd word, and it is not a word I expected to encounter, what it really means is impaired sensory gating. This is a core feature of Asperger’s, ADHD and schizophrenia.

One of the key risk genes for schizophrenia, DISC1, also affects HCN channels and this may account for some of the cognitive deficit found in schizophrenia. High level thinking is particularly affected.  It is thought that loss of DISC1 function in the PFC would likely prevent proper PDE4 function, leading to a dysregulated build-up of cAMP in dendritic spines resulting in excessive opening of HCN channels

Role of disrupted in schizophrenia 1 (DISC1) in stress-induced prefrontal cognitive dysfunction

I did wonder how nicotine fits in, since in earlier post we saw that α7 nAChR agonists, like nicotine, improve sensory gating and indeed that people with schizophrenia tend to be smokers. It turns out that nicotine is also an HCN channel blocker. For a change, everything seems to fit nicely together. There are different ways to block HCN channels, some of which are indirect. One common ADHD drug, Guanfacine, keeps these channels closed, but in a surprising way.

Alpha-2A adrenergic receptors near the HCN channels, on those dendritic spines, inhibit the production of cAMP and the HCN channels stay closed, allowing the information to pass through into the cell, connecting the network. These Alpha-2A adrenergic  receptors are stimulated by a natural brain chemical norepinephrine, or by drugs like Guanfacine.

Stress appears to flood PFC neurons with cAMP, which opens HCN channels, temporarily disconnects networks, and impairs higher cognitive abilities.

This would explain why stress makes people’s sensory gating problems get worse. So someone with Asperger’s would get more distracted/disturbed at exam time at school for example, or when he goes for a job interview. Reducing stress is another method to improve sensory gating and indeed cognition. In Monty, aged 14 with ASD, the only time he exhibits significantly impaired sensory gating, is when he has stopped all his Polypill therapies for several days. I think stress/anxiety is what has changed and this opens those HCN channels. Then even the sound of someone eating food next to him makes him angry.

Excessive opening of HCN channels might underlie many lapses in higher cognitive function.

While the researchers at Yale patented the idea of HCN blockers to improve cognition, we can see how other existing ideas to improve cognition may indeed have the same mechanism, most notably PDE4 inhibitors.

The University of Maastricht holds patents on the use of Roflumilast, a PDE4 inhibitor, to improve cognition; most interestingly, this takes effect at one fifth of the COPD dosage, for which it is an approved drug. At high doses PDE4 inhibitors have annoying side effects, but at low doses they tend to be trouble-free.

One effect of a PDE4 inhibitor is that it reduces cAMP. So a PDE4 inhibitor acts indirectly like an HCN blocker.

Not surprisingly recent research showed that low doses of Roflumilast improves sensory gating in those affected by this issue.

So rather than waiting for a brain selective HCN blocker, the potential exists to use a one fifth dose of Roflumilast today. This is something that should indeed be investigated across different types of cognitive dysfunction.

There are numerous dysfunctions that can impair cognition and they can occur in different diagnosis. For example impaired autophagy is a key feature of Huntington’s, impaired remyelination defines multiple sclerosis, low levels of nerve growth factor are a key feature of Rett syndrome. Less severe dysfunctions of these processes occur in entirely different conditions.

It is thought that people with Alzheimer’s might benefit from PDE4 inhibition. If it was me, I would try it in all types of dementia or cognitive loss of any kind.

PDE4 Inhibitors

There have been many mentions of PDE4 inhibitors elsewhere in this blog. They are broadly anti-inflammatory and anti-oxidant, but currently only widely used to treat asthma in Japan and COPD in Western countries. COPD is a kind of very severe asthma.

Traditionally a PDE4 inhibitor is thought of as drug used to block the degradative action of phosphodiesterase 4 (PDE4) on cyclic adenosine monophosphate (cAMP). That all sound complicated, just think of it as increasing cAMP.

Now cAMP is a messenger in many biological processes, one of which relates to PKA (Protein Kinase A). In autism we know that PKA, PKB and PKC are often disturbed. These PKs are very important because they have the ability to literally change the function of thousands of proteins in your body. This is similar to how epigenetic tags can switch on or switch off a particular gene. PKs, via a different mechanism we will look at in another post, change the function of proteins, so it is very important that you have the correct level of PKA, PKB and PKC.

We saw in a recent post that the Pitt Hopkins gene TCF4 is regulated by PKA and that under-expression of TCF4 is also a feature of some ID and schizophrenia. So more PKA, please.

The Intellectual Disability and Schizophrenia Associated Transcription Factor TCF4 Is Regulated by Neuronal Activity and Protein Kinase A 

You can use a PDE4 inhibitor to increase cAMP, which then increases PKA.

Other effects of PDE4 inhibitors

Today’s post is about sensory gating and the effect here of PDE4 inhibitors is via the effect of cAMP on those HCN channels in your tiny dendritic spines.

There are numerous other effects of PDE4 that may also be therapeutic. One interesting effect is that inhibition of PDE4 can mimic calorie restriction by activating AMPK/SIRT1 pathway.

Calorie restriction has just been shown in a large trial to be able to reverse type 2 diabetes, if initiated with a few years of the disease developing.

Humans have evolved based to periods of feast and famine. Periods of fasting may be therapeutic for many modern conditions.

Not surprisingly one side effect of PDE4 inhibitors is weight loss. Many psychiatric drugs cause troubling weight gain.

Acute administration of Roflumilast enhances sensory gating in healthy young humans in a randomized trial. 

Abstract

 

INTRODUCTION:

Sensory gating is a process involved in early information processing which prevents overstimulation of higher cortical areas by filtering sensory information. Research has shown that the process of sensory gating is disrupted in patients suffering from clinical disorders including attention deficit hyper activity disorder, schizophrenia, and Alzheimer's disease. Phosphodiesterase (PDE) inhibitors have received an increased interest as a tool to improve cognitive performance in both animals and man, including sensory gating.

METHODS:

The current study investigated the effects of the PDE4 inhibitor Roflumilast in a sensory gating paradigm in 20 healthy young human volunteers (age range 18-30 years). We applied a placebo-controlled randomized cross-over design and tested three doses (100, 300, 1000 μg).

RESULTS:

Results show that Roflumilast improves sensory gating in healthy young human volunteers only at the 100-μg dose. The effective dose of 100 μg is five times lower than the clinically approved dose for the treatment of acute exacerbations in chronic obstructive pulmonary disease (COPD). No side-effects, such as nausea and emesis, were observed at this dose. This means Roflumilast shows a beneficial effect on gating at a dose that had no adverse effects reported following single-dose administration in the present study.

CONCLUSION:

The PDE4 inhibitor Roflumilast has a favourable side-effect profile at a cognitively effective dose and could be considered as a treatment in disorders affected by disrupted sensory gating.

Treating Cognitive Impairment with Roflumilast, Maastricht University

Background Information

Selective phosphodiesterase (PDE) inhibition has been considered as a very promising target for cognition enhancement.

Roflumilast is a PDE4 inhibitor that has been developed by Takeda for Chronic Obstructive Pulmonary Disease (COPD). In recent year, Maastricht University has been collaborating with Takeda to develop Roflumilast for cognitive impairments

In 2015 Takeda sold COPD indication of Roflumilast to AstraZeneca, and ownership of IP for treatment of cognitive impairment returned to Maastricht University.

Compelling clinical results

A single administration of Roflumilast improves episodic memory in mice, and in young and elderly healthy subjects at a non-emetic dose

As shown in the figure, healthy (A) and memory impaired (B) elderly subjects showed better performances in the delayed recall of the Verbal Learning Task after roflumilast

Key Features and Advantages

Opportunities to reposition a clinically-proven safe compound with a well-established pharmacology.

Compelling preclinical and clinical evidences showing that Roflumilast effectively deliver to the brain to produce robust cognitive enhancement.

Pro-cognitive effects at low dose (5 times lower than COPD indication), which allows to circumvent the emetic effects commonly observed with other PDE4 inhibitors

Maastricht University has a strong IP protection extending to at least 2033.

Effect of Roflumilast on cognitive function in schizophrenia

PDE inhibitors in psychiatry--future options for dementia, depression and schizophrenia?

Author information

Abstract

Phosphodiesterases are key enzymes in cellular signalling pathways. They degrade cyclic nucleotides and their inhibition via specific inhibitors offers unique 'receptor-independent' opportunities to modify cellular function. An increasing number of in vitro and animal model studies point to innovative treatment options in neurology and psychiatry. This review critiques a selection of recent studies and developments with a focus on dementia/neuroprotection, depression and schizophrenia. Despite increased interest among the clinical neurosciences, there are still no approved PDE inhibitors for clinical use in neurology or psychiatry. Adverse effects are a major impediment for clinical approval. It is therefore necessary to search for more specific inhibitors at the level of different PDE sub-families and isoforms.

Brain Networks Strengthened By Closing Ion Channels, Research Could Lead To ADHD Treatment

The current study found that brain cells in PFC contain ion channels called hyperpolarization-activated cyclic nucleotide-gated channels (HCN) that reside on dendritic spines, the tiny protrusions on neurons that are specialized for receiving information. These channels can open when they are exposed to cAMP (cyclic adenosine monophosphate). When open, the information can no longer flow into the cell, and thus the network is effectively disconnected. Arnsten said inhibiting cAMP closes the channels and allows the network to reconnect.

Guanfacine can strengthen the connectivity of these networks by keeping these channels closed, thus improving working memory and reducing distractibility," she said. "This is the first time we have observed the mechanism of action of a psychotropic medication in such depth, at the level of ion channels."

Arnsten said the excessive opening of HCN channels might underlie many lapses in higher cognitive function. Stress, for example, appears to flood PFC neurons with cAMP, which opens HCN channels, temporarily disconnects networks, and impairs higher cognitive abilities.

The study also found alpha-2A adrenergic receptors near the channels that inhibit the production of cAMP and allow the information to pass through into the cell, connecting the network. These receptors are stimulated by a natural brain chemical  norepinephrine or by medications like guanfacine.

 “Guanfacine can strengthen the connectivity of these networks by keeping these channels closed, thus improving working memory and reducing distractibility,” she said. “This is the first time we have observed the mechanism of action of a psychotropic medication in such depth, at the level of ion channels.”

Yale has submitted a patent application on the use of HCN blockers for the treatment of PFC cognitive deficits based on the data reported in the Cell paper.

The full Yale paper:

α2A-Adrenoceptors Strengthen Working Memory Networks by Inhibiting cAMP-HCN Channel Signaling in Prefrontal Cortex

Guanfacine for the Treatment of Cognitive Disorders: A Century of Discoveries at Yale

The prefrontal cortex (PFC) is among the most evolved brain regions, contributing to our highest order cognitive abilities. It regulates behavior, thought, and emotion using working memory. Many cognitive disorders involve impairments of the PFC. A century of discoveries at Yale Medical School has revealed the neurobiology of PFC cognitive functions, as well as the molecular needs of these circuits. This work has led to the identification of therapeutic targets to treat cognitive disorders. Recent research has found that the noradrenergic α2A agonist guanfacine can improve PFC function by strengthening PFC network connections via inhibition of cAMP-potassium channel signaling in postsynaptic spines. Guanfacine is now being used to treat a variety of PFC cognitive disorders, including Tourette’s Syndrome and Attention Deficit Hyperactivity Disorder (ADHD). This article reviews the history of Yale discoveries on the neurobiology of PFC working memory function and the identification of guanfacine for treating cognitive disorders.

Nicotine blocks the hyperpolarization-activated current Ih and severely impairs the oscillatory behavior of oriens-lacunosum moleculare interneurons.

Molecular modeling suggests that, similarly to ZD 7288, nicotine and epibatidine directly bind to the inner pore of the HCN channels. It is therefore likely that nicotine severely influences rhythmogenesis and high cognitive functions in smokers.

Modulation of HCN channels in lateral septum by nicotine

Conclusion

I think many people stand to benefit from the drugs mentioned in today’s post, but for different biological reasons. A person with Pitt Hopkins may benefit from Roflumilast because it will upregulate PKA and then increase expression of their remaining TCF4 gene.

In a person with schizophrenia there are multiple reasons these drugs might help them and it will depend on which genes they have that are misexpressed (TCF4, DISC1 etc.).

In a person with idiopathic Asperger’s and impaired sensory gating it looks like the effect on HCN channels is what is important.

I think low dose Roflumilast has great potential for many. The Japanese drug Ibudilast very likely will provide similar benefits, but at what dosage?

PDE4 inhibitors do have side effects at higher doses in part because there are several different types of PDE4 (PDE4A, PDE4B, PDE4C etc) and different drugs effect different subtypes differently.

Ibudilast is used as a daily drug therapy for asthma in Japan and is being studied as a therapy for Multiple Sclerosis (MS) in the US.

Roflumilast is sold by Astra Zeneca as Daxas/Daliresp but at a high dose of 500mcg to treat flare ups of COPD (Chronic Obstructive Pulmonary Disease) it does cause troubling side effects, but it reduces your chance of dying from COPD.

The cognitive dose used in research is 100mcg. Higher doses had no cognitive/sensory gating benefit.

Further investigation of the ADHD drug Guanfacine should be made, because some of the people who benefit from a PDE4 inhibitor might get a similar effect from Guanfacine. People with Pitt Hopkins would not be in this category. A person with Asperger’s and impaired sensory dating should respond to Guanfacine, a cheap drug.

At the end of the day, choice of therapy will come down to side effects and cost. In the US, Roflumilast is expensive ($330), seven times more expensive than in some other countries; in the UK the price of the same 30 tablets is $50. One pack would be enough for 5 months at the suggested dose.

Glutamate Inhibitors to Treat Some Autism and ADHD

 A festive queue at the pharmacy for Glutamate Inhibitors

We have now established that much autism and indeed other disorders, from Down Syndrome to Schizophrenia, features a degree of excitatory/inhibitory (E/I) imbalance.

It is very likely that there are multiple underlying causes for this and so there may be multiple treatments.  We can even potentially use a treatment for one cause (ALS) to improve outcomes in others.  So we can (partially) solve a problem without fully understanding its origin, as frequently is the case in biology.

An E/I imbalance might cause anxiety in the adult with Asperger (treatable with Baclofen), contribute to MR/ID in the child with Down Syndrome and contribute to seizures and cognitive loss in someone with severe autism.

Very interestingly in the comments to a previous post, Agnieszka has pointed out why common penicillin type antibiotics (beta-lactams) improve many people’s autism.  This is very common observation and our other guest blogger Seth Bittker found the same in his son. Nat’s guest speaker at her autism conference also found this in his son.

The Glutamate Transporter 1 (GLT-1) is a protein that in humans is encoded by the SLC1A2 gene.   It is the principal transporter that clears the excitatory neurotransmitter glutamate from the extracellular space at synapses in the central nervous system. Glutamate clearance is necessary for proper synaptic activation and to prevent neuronal damage from excessive activation of glutamate receptors. Glutamate is an excitatory neurotransmitter, so it encourages neurons to fire.

By upregulating the GLT1 transporter you increase the inactivation of glutamate and so shift the Excitatory/Inhibitory balance towards inhibitory.

Agnieszka highlighted this paper from Johns Hopkins:-

Beta-lactam antibiotics offer neuroprotection by increasing glutamate transporter expression

Glutamate is the principal excitatory neurotransmitter in the nervous system. Inactivation of synaptic glutamate is handled by the glutamate transporter GLT1 (also known as EAAT2; refs 1, 2), the physiologically dominant astroglial protein. In spite of its critical importance in normal and abnormal synaptic activity, no practical pharmaceutical can positively modulate this protein. Animal studies show that the protein is important for normal excitatory synaptic transmission, while its dysfunction is implicated in acute and chronic neurological disorders, including amyotrophic lateral sclerosis (ALS), stroke, brain tumours and epilepsy. Using a blinded screen of 1,040 FDA-approved drugs and nutritionals, we discovered that many beta-lactam antibiotics are potent stimulators of GLT1 expression. Furthermore, this action appears to be mediated through increased transcription of the GLT1 gene. beta-Lactams and various semi-synthetic derivatives are potent antibiotics that act to inhibit bacterial synthetic pathways. When delivered to animals, the beta-lactam ceftriaxone increased both brain expression of GLT1 and its biochemical and functional activity. Glutamate transporters are important in preventing glutamate neurotoxicity. Ceftriaxone was neuroprotective in vitro when used in models of ischaemic injury and motor neuron degeneration, both based in part on glutamate toxicity. When used in an animal model of the fatal disease ALS, the drug delayed loss of neurons and muscle strength, and increased mouse survival. Thus these studies provide a class of potential neurotherapeutics that act to modulate the expression of glutamate neurotransmitter transporters via gene activation.

It actually gets more interesting and relevant to treatment.

Mutations in SLC1A2 which decrease expression of the GLT-1 protein are associated with amyotrophic lateral sclerosis (ALS). 

The drug riluzole approved for the treatment of ALS upregulates GLT-1.

This would suggest that Agnieszka, Seth and John Rodakis might want to pay a visit to the pharmacy and pick up some riluzole.  It is certainly worth investigating.

I did check and there is even a trial on Riluzole in autism and evidence of existing off-label use.  They have not of course made Agnieszka’s connection; they seem to be just trying it because nothing else seems to help. That really is trial and error and makes this blog look positively scientific by comparison.

A Pilot Study of Riluzole Versus Placebo in the Treatment of Children and Adolescents With ASD(RILISE)

Drug: Riluzole

50mg once daily (QD) for 12 weeks for participants 6-11 years old; 50mg twice daily (BID) for 12 weeks for participants 12-17 years old

Riluzole in Autistic Disorder

A reformulation of riluzole that originated at Yale University and is known by the code name BHV-0223 is under development for the treatment of generalized anxiety disorder and mood disorders  by Biohaven Pharmaceuticals.

  

Anyway, are there any other ways to inhibit Glutamate?

Yes, our reader Valentine just stumbled on one, tizanidine, but there are at least two others. 

α2 adrenergic agonists

Three other known inhibitors of glutamate happen to be α2 adrenergic agonists

·        Clonidine

·        Guanfacine

·        Tizanidine

All three of the above are already used in ADHD and sometimes in autism, but not to reduce glutamate.

I wrote a post about Clonidine use in autism a long time ago.

Clonidine, ADHD and Autism

Guanfacine is an ADHD drug known to inhibit glutamate release.

Guanfacine shown safe and effective in autism treatment

At five sites, children with ASD and moderate to severe hyperactivity were either given guanfacine or a placebo tablet for eight weeks, in a randomized and double-blind clinical trial. The research team collected information from parents and measured each child’s overall response. After eight weeks of treatment, extended release guanfacine was superior to placebo for decreasing hyperactivity and impulsiveness.

Our reader Valentina seems to have stumbled upon tizanidine, but finds it helpful for her son. Tizanidine is a α2 adrenergic agonists but also inhibits glutamate.  It is one of the drugs used off-label by Dr Chez in ADHD and autism

Pediatric safety of tizanidine: clinical adverse event database and retrospective chart assessment

Henney HR 3rd¹, Chez M.

CONCLUSION:

The overall safety of tizanidine in the pediatric group appeared good; however, the adverse event profile differed from that in adults. This difference most likely reflects the off-label use of tizanidine as adjunctive treatment for attention disorders and autism. The frequency and nature of adverse events in adults were consistent with the tizanidine prescribing information as reported for its approved indication, i.e. management of spasticity.

Conclusion

Ideally you would have a comparison of the four drugs:

·        Riluzole

·        Tizanidine

·        Clonidine

·        Guanfacine

We know clonidine is not an autism wonder drug, but then what is?

I think Riluzole is likely to be a good one, but very likely what works best will vary from person to person.

Perhaps a positive response to beta-lactam (penicillin) antibiotics is a biomarker for people who will respond to Riluzole? It should be.