Drug Interaction Report

GENERALLY AVOID: Patients exposed to photosensitizing agents around the same time as oral aminolevulinic acid may be at an increased risk of a phototoxic skin reaction (severe sunburn). These agents have each been individually associated with photosensitivity reactions and may have additive effects when used together. Medicinal products with known phototoxic or photoallergic potential include, but are not limited to, hypericin-containing products (e.g., St. John's Wort), griseofulvin, thiazide diuretics, sulfonylureas, phenothiazines, sulfonamides, quinolones, tetracyclines, and topical aminolevulinate preparations. There is one case report of a severe sunburn lasting for 5 days in a patient who used oral aminolevulinic acid concurrently with a hypericin extract.

MANAGEMENT: Photosensitizing agents (e.g., fluoroquinolones, phenothiazines, retinoids, sulfonamides, sulfonylureas, tetracyclines, thiazide diuretics, griseofulvin, St. John's wort) and topical preparations containing aminolevulinic acid should be avoided for 24 hours before and after oral administration of aminolevulinic acid. Some authorities recommend avoiding exposure to any photosensitizing agent for up to 2 weeks after oral administration of aminolevulinic acid. Patients should also avoid exposure of the eyes and skin to sunlight and bright indoor lights (e.g., examination lamps, operating room lamps, tanning beds, lights at close proximity) for 48 hours after treatment.

GENERALLY AVOID: An isolated case report suggests that foods containing large amounts of tyramine may precipitate a hypertensive crisis in patients treated with St. John's wort. The mechanism of interaction is unknown, as St. John's wort is not thought to possess monoamine oxidase (MAO) inhibiting activity at concentrations achieved in vivo. The case patient was a 41-year-old man who had been taking St. John's wort for seven days prior to presentation at the emergency room with confusion and disorientation. The patient recalled last eating aged cheese and having a glass of red wine approximately 10 hours prior to admission. No other cause of delirium or hypertension could be identified. In addition, alcohol may potentiate some of the pharmacologic effects of St. John's wort. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

MANAGEMENT: Until further information is available, patients treated with St. John's wort should consider avoiding consumption of protein foods in which aging or breakdown of protein is used to increase flavor. These foods include cheese (particularly strong, aged or processed cheeses), sour cream, wine (particularly red wine), champagne, beer, pickled herring, anchovies, caviar, shrimp paste, liver (particularly chicken liver), dry sausage, figs, raisins, bananas, avocados, chocolate, soy sauce, bean curd, yogurt, papaya products, meat tenderizers, fava beans, protein extracts, and dietary supplements. Caffeine may also precipitate hypertensive crisis so its intake should be minimized as well. Patients should also be advised to avoid or limit consumption of alcohol.