Australia. Since November 1972, the Adverse Drug Reactions Committee has received 332 reports of suspected drug-induced gynaecomastia in patients whose ages ranged from 8 to 91 years (median 62). In many cases a drug cause was not suspected initially and therapy was continued for several weeks or months after onset. Four reports were accompanied by the results of excision biopsies which confirmed non-malignancy. The drugs most commonly reported (representing over 75% of the total) are listed below (10 reports or more):

Anti-ulcer drugs (cimetidine, ranitidine, famotidine and omeprazole) account for 30% of the total.

Drug-induced gynaecomastia is usually bilateral but often asymmetric and its development is considered to be related both to the daily dose and the duration of therapy. It is generally reversible after withdrawal of the drug, although complete recovery may take several months. The condition is often painful and may result in concerns about possible malignancy. A possible drug cause should always be considered before surgery.

Reference: Australian Adverse Drug Reactions Bulletin Vol. 16, No. 3, August 1997.

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