Blockade of carcinoid flush with cimetidine and clonidine.

A patient with the carcinoid syndrome had flushes provoked by the ingestion of water at 60 degrees C, red wine, and milk chocolate. The patient was given sequential courses of clonidine hydrochloride, chlorpheniramine maleate, cimetidine, and a combination of chlorpheniramine and cimetidine. No flushes followed ingestion of red wine or milk chocolate during treatment courses with cimetidine (alone or in combination with chlorpheniramine) or clonidine. Chlorpheniramine alone did not affect flushing. None of the pharmacologic agents altered the flushing response to the ingestion of water at 60 degrees C.