The relationship between prolactin levels and clinical ratings in manic patients treated with oral and intravenous test doses of haloperidol

Abstract

SYNOPSIS Twelve manic patients were treated for 2 weeks with oral haloperidol; in 6 patients treatment commenced with intravenous haloperidol, and intravenous ‘test’ doses were given after 1, 3–5 and 14 days of oral medication. From 24 hours to 14 days baseline serum prolactin levels rose towards a plateau, as did the improvement in clinical ratings. After the first intravenous test doses of haloperidol, prolactin levels peaked at 1 hour; however, they fell to a low point at 24 hours, and no response to further test doses was seen for 3–5 days. The response tended to return at 14 days. The mechanisms underlying the changes in prolactin levels, and in clinical state, are discussed.