Interactions Between Antiretroviral Agents & Alternative Therapies

Interactions Between Antiretroviral Agents & Alternative Therapies

A 3 period, two week, open-label, fixed schedule (300mg TID) study using a drug probe cocktail to determine the effect of St John's wort on cytochrome P450 enzyme activity in 12 healthy volunteers found that St John's wort induced the capacity of CYP 3A4 but failed to influence CYP2C9, CYP1A2, or CYP2D6 activity.

Not only does this research add to the pool of evidence showing that St John's wort is an inducer of CYP3A4, the results also cast doubt on the ability of St John's wort to alter exposure to antiretroviral therapy that is metabolized by cytochrome P450 enzymes other than CYP3A4.

Wang Z, Gorski JC, Hamman MA, et al. The effects of St John's wort (Hypericum perforatum) on human cytochrome P450 activity. Clin Pharmacol Ther 2001; 70 (4): 317-26.

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