Metergoline versus bromocriptine in the prevention of puerperal lactation. A double-blind clinical trial.

In a double blind study of the prevention of puerperal lactation, the clinical efficacy of two antiprolactin drugs was compared: metergoline 4 mg tid and bromocriptine 2.5 mg bid were both given for 7 days. An additional 7 days of treatment was administered to 16 patients in whom mammary activity was still present or appeared in the following 3 days. The first 7 day period of treatment was effective in 16/20 women receiving metergoline and in 7/20 on bromocriptine (p less than 0.02); the second period of treatment was effective in all remaining patients. These data indicate that metergoline acts rapidly to arrest puerperal lactation, possibly by a mechanism different from that of bromocriptine.