St. John's Wort (Hypericum perforatum) (cont.)

Pharmacy Author:
Medical and Pharmacy Editor:

SIDE EFFECTS: The most common side effects associated with St. John's wort treatment are

  • asfunction.



STORAGE: Capsules and caplets should be stored at room temperature between 15 C and 30 C (59 F and 86 F).

PRESCRIBED FOR: St. John's wort is an over-the-counter (OTC) dietary supplement that is used for treatment of mild depression. It is also used to treat symptoms of mild anxiety and occasional episodes of sleep disturbances (insomnia), among others.

DOSING: Dietary supplements such as St. John's wort are not regulated by the FDA, and are not subject to rigorous clinical studies that evaluate standardized drug dosages. Read product labels and discuss dosing with your doctor before taking this dietary supplement.

The most common dosage that has been used in the majority of studies is 0.3% hypericin or 5% hyperforin in a dosage of 300 to 400 mg three times daily.

DRUG INTERACTIONS: St. John's wort increases activity of several liver enzymes. Consequently, St. John's wort may decrease blood levels of drugs that are metabolized or broken-down by these enzymes. Examples of such drugs are warfarin (Coumadin), fluconazole (Diflucan), voriconazole (Vfend), itraconazole (Sporanox), fentanyl (Sublimaze), digoxin (Lanoxin), birth control pills and many other drugs.

St. John's wort should be avoided in patients taking prescription antidepressants due to the risk of serotonin syndrome. Symptoms of serotonin syndrome include agitation, hyperthermia (extreme body temperature), sweating, rapid heartbeat, and neuromuscular disturbances.

Additionally, St. John's wort may interact with other prescription medications. All patients should speak to their doctor or pharmacist before taking St. John's wort.

PREGNANCY: Due to the lack of safety data, St. John's wort is not recommended during pregnancy.

NURSING MOTHERS: Due to the lack of safety data, St. John's wort is not recommended during breastfeeding. It is not known if St. John's wort is excreted into breast milk.

REFERENCE: "Herbal Medicine: Biomolecular and Clinical Aspects. 2nd edition." Benzie IFF, Wachtel-Galor S, editors. Boca Raton (FL): CRC Press; 2011.

Medically Reviewed by a Doctor on 10/24/2014

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