Tuesday, 23 September 2014

Gut issues in autism impacting on drug availability and absorption

As indicated in a recent post, I was really rather pleased to see the paper by Andrew Heitzer and colleagues [1] (open-access) asking the important question: Should clinical trial research of psychotropic medication in autism control for gastrointestinal symptoms? Some media about the study can also be found here.
"You write "Born to Kill" on your helmet
and you wear a peace button".

The answer is of course, yes and not just when it comes to psychotropic medicines either, given that gastrointestinal (GI) symptoms both functional and more pathological, are by no means an uncommon event when a diagnosis of autism is received (see here).

As anyone with an interest in pharmcokinetics and pharmacodynamics should be able to tell you, various factors can affect a persons response to medication, particularly medication delivered orally (by mouth). Outside of medicines interactions, ageing is one of the more well-studied factors pertinent to drug response as per the review by Mangoni & Jackson [2] for example, but there are other suggestions on the horizon. Indeed, I might also take this opportunity to link to some of the work by Prof. Jeremy Nicholson and colleagues [3] talking about how gut bacteria may play a role in drug metabolism. This area may be particularly pertinent to autism given this research teams' previous forays into autism science (see here) and the growing interest in the gut microbiota and autism (see here).

There are various other factors which may also affect drug response in relation to autism such as stomach acid conditions (see here) and even drug transporter capability (see here). This outside of adherence to instructions like taking medication with water or avoiding food/certain foods when taking particular medicines, which one should never assume are just followed.

Of course there are other ways in which medication, when indicated, can potentially be reformulated to overcome some of these issues. I've talked before about some work our research group were involved with looking at making up the opiate antagonist naltrexone into a cream (see here). Although not necessarily a big fan of the sweeping statements made about oxytocin and autism (see here), I've likewise always been interested in the intra-nasal route of drug administration. There are other ways too (bearing in mind I'm making no value judgements on these).

So once again, yes, as part of good medicines management, clinicians and researchers need to be mindful that comorbid issues like GI symptoms can potentially affect the workings of various medicines if and when required by people with autism.

Music then. Bohemian Like You by The Dandy Warhols.

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[1] Heitzer AM. et al. Should clinical trial research of psychotropic medication in autism control for gastrointestinal symptoms? J Clinical Pharmacology. 2014. 6 May.

[2] Mangoni AA. & Jackson SHD. Age-related changes in pharmacokinetics and pharmacodynamics: basic principles and practical applications. Br J Clin Pharmacol. Jan 2004; 57(1): 6–14.

[3] Clayton TA. et al. Pharmacometabonomic identification of a significant host-microbiome metabolic interaction affecting human drug metabolism. Proc Natl Acad Sci U S A. 2009 Aug 25;106(34):14728-33.

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ResearchBlogging.org Heitzer AM, Job MA, Pandit NK, & Valdovinos MG (2014). Should clinical trial research of psychotropic medication in autism control for gastrointestinal symptoms? Journal of clinical pharmacology PMID: 24788353