They are contraindicated in acute flare-ups of psoriasis, since their systemic absorption would be increased. Side effects include excessive irritation, hypersensitivity, and photosensitivity. Additionally, exposure to sunlight will increase the risk of cancer as an extension of the pharmacologic effect of the preparation. They may also discolour nails and white or grey hair. Systemic absorption may cause nephrotoxicity, hepatoxicity, or cancer.
Application is usually at bedtime, with the drug being washed off the next morning.
Application should be made wearing rubber gloves to limit absorption. Its actions are reversible. If no reaction occurs, the patient should apply the medication twice daily. If no improvement is seen within 2-3 months, the medication should be discontinued. Agents Used in Acne Topical antibiotics provide efficacious therapy in the treatment of severe acne.