Minocycline pigmentation of heart valves

Minocycline, a derivative of tetracycline, is a broad spectrum antibiotic u sed in the treatment of gram-positive and gram-negative infections. Benitz et al. (1) were the first to report black discoloration of the thyroid glan d in rats, dogs, and monkeys given minocycline. Since that time, there have been numerous reports in the literature describing minocycline related bla ck pigmentation of the skin, thyroid gland, and other sites. We report an u nusual case of minocycline induced pigmentation of the cardiac valves and c oronary vessels. The pigment stained with Fontana-Masson and was reduced wi th bleaching. The exact nature of the pigment is unclear; however, various theories have been advocated. Ochronosis is another cause of black pigmenta tion of the heart valves; the clinical history should allow distinction bet ween the two. (C) 1999 by Elsevier Science Inc.