Previous issues of the Allergic Reaction have had several articles about the human microbiome and its impact on health including its effects on the immune system and other systems. Now, add an additional new finding to this list. This research was recently published in Nature and it studied interactions of gut bacteria with oral drugs.
Among people who have the same disease a particular medicine can vary greatly in its effectiveness and side effects. Much of this variability has been attributed to genetic differences. This new research indicates that some of the variability is also due to the patients’ gut flora.
Scientists studied the effects of 15 drugs on 25 strains of human gut bacteria and found a remarkable variability in drug-bacteria interactions. For a given medicine some bacteria stored it without modifying it; whereas, other bacteria modified it either to make it more or less bioactive. Either way, the bacteria can lead to the patient receiving a bigger dose or a lower dose of the medicine than was intended. Getting a bigger dose than intended has potential to lead to greater incidence of side effects.
The other side of the research coin showed that some of the drugs altered the growth rate and metabolism of the bacteria. This in turn led to an increase or decrease in the molecules secreted by the gut bacteria including: hormones, neurotransmitters and inflammatory molecules.
At first blush many people are going to feel frustrated by this new level of complexity in how medicines affect us, but scientists have known for a long time this variability in patient response and it was dealt with via “trial and error”. Hopefully, this new research will lead to a scientific algorhythm for proper dosing based on individual microbiome.