The effects of high physical activity on pharmacokinetic drug interactions

With the development of new drugs, it is common practice for drug manufacturers to measure their pharmacokinetic parameters. This testing involves the discovery of the absorption, distribution, metabolic, excretory and toxicological properties of drugs. The testing is usually done in non-stressful conditions at rest, however, this does not necessarily tell the entire picture as there is increasing knowledge about the effects that high levels of physical activity can have on the pharmacokinetics of some medications.

This review discusses the alterations that physical activity can have on the absorption, distribution, metabolism and elimination parameters of commonly used medications, and clinical outcomes data are reported when known, demonstrating that an interaction exists between exercise and certain medications. This drug-exercise pharmacokinetic interaction alters the performance of medications especially under conditions where exercise is performed for a long period of time. Particular medications that may be affected are those with a narrow therapeutic dosing range, such as digoxin, theophylline and warfarin. Other important medications include insulin and those administered via a transdermal patch drug delivery system. For this review, a literature search was performed between 1966 and 2010.

Patients and healthcare providers should be aware that exercise can adversely affect the way some medications are intended to work. Patients taking certain medications should be closely monitored when performing high amounts of physical activity.