Gynecomastia from spironolactone

Epierenone has been reported to produce less gynecomastia than spironolactone (6,7). In patients with gynecomastia from spironolactone, epierenone can be substituted and gynecomastia status reassessed. 

The diuretic effect of spironolactone develops fully only with continuous administration for several days. Two possible explanations are (1) the conversion of spironolactone into and accumulation of the more slowly eliminated metabolite canrenone (2) an inhibition of aldosterone-stimulated protein synthesis would become noticeable only if existing proteins had become nonfunctional and needed to be replaced by de novo synthesis. A particular adverse effect results from interference with gonadal hormones, as evidenced by the development of gynecomastia (enlargement of male breast). Clinical uses include conditions of increased aldosterone secretion, e.g., liver cirrhosis with ascites. 

Spironolactone as a diuretic is discussed in Chapter 15. The drug has benefits in heart failure greater than those predicted from its diuretic effects alone (see Chapter 13). Adverse effects reported for spironolactone include hyperkalemia, cardiac arrhythmia, menstrual abnormalities, gynecomastia, sedation, headache, gastrointestinal disturbances, and skin rashes. 

The results from EPHESUS have raised the question of which aldosterone blocker, spironolactone or eplerenone, should be used preferentially. Currently, there are no data to support that the more selective but more expensive eplerenone is superior to or should be preferred to the less expensive generic spironolactone unless a patient has experienced gynecomastia, breast pain, or impotence while receiving spironolactone. Einally, it should be noted that hyperkalemia is just as likely to appear with both these agents. 

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