Composition
Tab 10 mg: Methoxsalen 10 mg. Lotion/Oint 1%: Methoxsalen 1%. Tab 10 mg: Methoxsalen 10 mg. Oint 1%: Methoxsalen 1%.
Indications & Dosage
Idiopathic vitiligo: ORAL: Adults & Children above 12 yrs: 20 mg/day 2-4 hr before exposure to UVA or sunlight, take with milk or after food as a single dose or in 2 divided doses, approx 30 min apart to minimize GI side effects. The therapy should be on alternate days & never for 2 consecutive days. Max dose: 0.6 mg/kg. Chronic Psoriasis: ORAL: Adults: 10-70 mg 1.5-2 hr before exposure to UVA, administered 2-3 times wkly. Vitiliginous lesions: TOPICAL: Adults: The lotion/cream after dilution to 0.1% or 0.01% applied once weekly for 6-9 months. Surrounding skin should be protected by an opaque screen. The treated area should be exposed to UVA alter waiting up to 2 hr. After exposure the lesion should be washed and protected from light for up to 48 hr or longer. Psoriasis: TOPICAL: Adults: The preparation is diluted 0.15% (or to 0.015%), applied to the affected area 15 min before UVA exposure. Alternatively whole body bath or hand/foot soaks given twice a week have also been recommended (See literature for procedure).
Contraindications
Diseases associated with light sensitivity (lupus erythematosus, porphyria), hypertension, heart, hepatic or renal failure.
Precautions
Protect eyes & skin against complementary sun exposure after controlled UV irradiation. Monitor patients on possible long-term risks of photo-chemotherapy e.g. skin ageing, changes in pigmentation, risk of basal cell epithelioma & cataract.
Interactions
Photosensitizing agents e.g. anthracin, coal tar, griseofulvin, phenothiazine, nalidixic acid, halogenated salicylamide, sulphonamides, tetracycline, thiazides, organic dyes.
Side Effects
Oedema, hypotension, nervousness, vertigo, depression, painful blistering, burning, pruritus, hypo-pigmentation, rash. cheilitis. erythema, itching, nausea, loss of muscle coordination.