Minocycline treatment of tetracycline-resistant and tetracycline-responsive acne vulgaris.

The purpose of the study presented herein was to determine the safety and efficacy of minocycline in patients whose acne vulgaris failed to respond adequately to tetracycline therapy and to confirm continued improvement in tetracycline-responsive patients when minocycline was substituted for tetracycline. Thirty-six acne vulgaris patients were given oral tetracycline (250 mg four times a day) for six weeks, followed by oral minocycline (50 mg three times a day) for six weeks. An analysis of the increase or decrease in total lesion counts obtained at biweekly intervals revealed that minocycline caused statically significant improvement both in patients who did not respond to tetracycline and in patients who did respond to tetracycline. Patients who did not respond to tetracycline therapy achieved a mean decrease of 54 percent in lesions after after six weeks of minocycline treatment. In tetracycline-responsive patients, six weeks' treatment with tetracycline caused a 33.5 percent mean decrease in the lesion count. When these patients received minocycline for a subsequent six-week period, the mean lesion count decreased by an additional 60 percent. Only one patient developed a side effect: severe itching and urticaria in a minocycline-treated subject warranted discontinuance of therapy. Minocycline was a safe and effective agent in the treatment of acne both in tetracycline-resistant and in tetracycline-responsive patients.