Primary prevention

Avoidance of oestrogenising agents may be greatly facilitated by judicious prescribing. With respect to commonly prescribed medicines, select those that are less likely to lead to male breast enlargement.

The following agents are listed in order of increasing risk for gynaecomastia:[28][30][31][36][38]​​[52]​​​[53]

  • H2 antagonists: cimetidine

  • Calcium-channel blockers: diltiazem < nifedipine

  • Aldosterone antagonists: eplerenone < spironolactone

  • Testosterone replacement in hypogonadal men: transdermal patch or gel < intramuscular

  • Prostate cancer therapies: bilateral orchiectomy < gonadotrophin-releasing hormone agonist < non-steroidal anti-androgen therapy < diethylstilbestrol < oestrogen.

Consider the following when bicalutamide or flutamide are used in the management of prostate cancer:[54]​​[55][56][57]​​​​​[58][59][60]​​

  • Prophylactic tamoxifen reduces development of gynaecomastia

  • Low-dose breast irradiation (10-15 gray units) reduces development of gynaecomastia, but is less effective than tamoxifen

  • The aromatase inhibitor anastrozole is no more effective than placebo in preventing gynaecomastia.

Prevention of obesity, in theory, should also reduce the development of gynaecomastia.

Secondary prevention

Preventative intent is generally limited to patients with prostate cancer, in which selective oestrogen modulation may begin concurrently with anti-androgen. However, even in these patients, only a minority will develop gynaecomastia.

In the vast majority of cases, gynaecomastia is treated symptomatically. Only those troubled by the condition require treatment.

Use of this content is subject to our disclaimer