Gut bacteria may change the way many drugs work in the body
Not to take away from these findings, but in general, individual genetics can radically change the way many drugs work, and even doctors seem blissfully unaware of this. Caffeine, for example, has a different elimination half-life based on your genetics. There are also genetic polymorphisms in adenosine and dopamine receptors that can change its effects: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4242593/. Another obvious example is how some people can't process alcohol.If you think about this for a minute, it sheds some light into how primitive medical research is. We generally assess the effectiveness of a drug based on how it affects one metric on average for a large group of people. It could well be that a drug is helpful to some and detrimental to others based on genetics, microbiome, etc. It follows that we are very likely to be giving people drugs that are harmful to them, and rejecting drugs in medical studies that could be helpful to some but are unhelpful to most.