The gut microbiome is the community of microbes inhabiting the human gastrointestinal tract, which contains nearly 2000 bacterial species. In addition to host elimination pathways (i.e. liver metabolism and renal excretion), the gut microbiota also plays important roles in drug metabolism through secretion of drug-metabolizing enzymes or microbiota-host co-metabolism. While the impact of gut microbiota on drug metabolism has been investigated for decades, data are only available for about 40 drugs or natural products.1 Previous research has implicated the gut microbiome in the co-metabolism of various medications, including acetaminophen, digoxin, simvastatin, and omeprazole.

Recently the interplay of the gut microbiome with human drug therapy has garnered renewed interest. For example, a group of authors at Columbia University in New York recently evaluated the relationship between the gut microbiome and tacrolimus and showed that gut improved microbial diversity is associated with higher tacrolimus dosing requirements early after heart transplantation.2 Other researchers are also exploring the effect on the gut microbiome on a wide range of medications, including cardiovascular, psychiatric, and antimicrobial agent.