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.

ADJUST DOSING INTERVAL: Food may reduce the oral absorption and bioavailability of levofloxacin. According to the drug product labeling, administration of levofloxacin 500 mg with food prolonged the time to peak concentration by 1 hour and decreased the Cmax decreased by 25% following administration of the oral solution and by 14% following administration of the oral tablet.

MANAGEMENT: To ensure maximal and consistent oral absorption, levofloxacin oral solution should be taken at least one hour before or two hours after meals. For administration of the oral solution with continuous enteral nutrition, some experts recommend that the tube feeding should be interrupted for one hour before and two hours after the dose of levofloxacin. The oral tablets may be taken without regard to food.