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: Concurrent use of ethanol and phenothiazines may result in additive CNS depression and psychomotor impairment. Also, ethanol may precipitate dystonic reactions in patients who are taking phenothiazines. The two drugs probably act on different sites in the brain, although the exact mechanism of the interaction is not known.

MANAGEMENT: Patients should be advised to avoid alcohol during phenothiazine therapy.