Effect of three serotonin antagonists on plasma prolactin response to suckling in puerperal women.

The effect of the acute administration of three serotonin antagonists on plasma PRL levels and on the PRL response to suckling was investigated in a group of puerperal women. A single oral dose of metergoline or methysergide induced a significant decrease of plasma PRL levels and abolished the PRL response to suckling. Cyproheptadine administration did not modify either the plasma PRL levels or the PRL response to suckling. These results are discussed in light of the known pharmacological properties of the three antiserotonergic drugs.