Inflammation is associated with down regulations of hepatic and extrahepatic CYP enzymes drug metabolism.
The CYP represent a superfamily of enzymes with a key role in the activation or inactivation of a plethora of therapeutic agents. CYP enzymes are involved in the metabolism of xenobiotic substances. Cytochromes present intra- or interindividual and intra- or interethnic genetic polymorphisms. Variations in the pharmacokinetic drug profile are linked to the rising toxicity following a declining metabolism, reduced efficacy of the drug, adverse drug interaction, and increasing production of toxic metabolites. The high-metabolic rate of the intestinal microbiota is due to its many enzymes which catalyze reactions in phase I and II drug metabolism. In case of a compromised intestinal barrier, there may be an increase in paracellular passive absorption.
It is evident that high-microbial abundance following intestinal disturbances, environment, aging, or food-associated diseases promotes the microbial metabolism of a drug before absorption.
Above link Includes CDC Vaccine Excipient list of xenobiotics