Center for Drug Evaluation & Research health advisories and guidances should be amended to communicate potential interactions of St. John's wort with certain types of Rx drugs, CHPA tells FDA.

In a citizen petition filed June 20, the Consumer Healthcare Products Association suggests prescription drug information should recognize the herbal as "a dietary constituent that may interact with drugs known to be metabolized by the cytochrome P450 pathway."

CHPA also asks the agency to require dietary supplements containing the herbal to carry a label statement pertaining to potential Rx interactions. The trade group points to its own voluntary labeling program that requires member companies' St. John's wort products to caution: "If you are taking a prescription drug, ask a health professional" (¹ Also see "St. John's Wort, Rx Drug Use Warning Adopted By CHPA" - Pink Sheet, 8 May, 2000.).

The association's program allows the St. John's wort warning to be combined with other voluntary labeling statements, such as the group's pregnancy/nursing warning. CHPA has petitioned FDA to require pregnancy/nursing label statements on certain types of supplements (² Also see "OTC Model For Dietary Supplement Pregnancy Labeling Proposed By CHPA" - Pink Sheet, 22 May, 2000.).

CHPA cites FDA's Feb. 10 public health advisory on interaction risks between St. John's wort and HIV protease inhibitors. The advisory was prompted by publication in The Lancet of a National Institutes of Health study showing the herbal compromises the antiviral drugs' effectiveness, possibly because the drugs are metabolized along the P450 pathway.

Many Rx drugs used to treat heart disease, depression, seizure and cancer, and to prevent transplant rejection or pregnancy also are metabolized along the P450 pathway, FDA noted, and health care providers should alert patients to potential interactions. FDA requested protease inhibitor sponsors update labeling to include St. John's wort warnings; an agency working group is examining labeling of other pertinent drugs.

In addition to the NIH study, CHPA points to several recent published reports of St. John's wort interactions with Rx drugs, including antidepressants and digoxin, as well as studies suggesting possible mechanisms of action for the interactions.

CHPA requests a one-year compliance deadline from publication of a final rule on St. John's wort supplement labeling.

FDA Notices, Guidances Should Reflect St. John's Wort Interaction - CHPA

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