Serious burns might occur from ultraviolet radiation or sunlight if recommended dose and/or exposure schedule is not maintained. Eyes should be shielded from direct and indirect sunlight for 24 hours to prevent possible formation of cataracts. Therapy may lead to increased risk of skin cancer (basal cell, melanoma and squamous cell). Use with caution in multiple basal cell carcinomas or history of basal cell carcinoma, in cardiovascular disease (may not be able to tolerate the heat stress or prolonged standing related to UVA treatment conditions), and in hepatic impairment (hepatic metabolism). If used for treating psoriasis, should be administered only in conjunction with scheduled controlled doses of long-wave ultraviolet radiation. If used for treating vitiligo, should be used in conjunction with controlled doses of long-wave ultraviolet radiation or sunlight. Use caution with other (systemic or topical) photosensitizing drugs (e.g. thiazides, tetracyclines, fluoroquinolones, phenothiazines, sulfonamides, anthralin, coal tar preparations). Use with caution in the elderly.