Metoclopramide and domperidone block the antihypertensive effect of bromocriptime in hypertensive patients / Loa bloqueadores metadopramida y domperidona en pacientes hipertensos y el efecto antihipertensivo de la bromocriptina

RESUMO

This study was conduced in normotensive and hypertensive patients at the Vargas Hospital of Caracas. Normotensive subjects received, in a crossover fashion, placebo, metoclopramide or domperidone, 40 mg of each drug daily for one week. The first group of patients under placebo for one(1) week received a single 2.5 mg oral dose bromocriptine (Br). The second group of patients received 30 mg of metoclopramide (MTC) daily (divided in 3 doses) for week. At the end of period a single dose of 2.5 mg of Br was given to each patient . The third group received domperidone (DOMP) during one week at 30 mg/daily dose to eight hypertesive patients and then a single dose of 2.5 mg Br. Cardiovascular and biochemical parameters including arterial pressure, heart rate, plasma renin activity, and plasma aldosterone concentration were evaluated during the 6 hour period before and after the administration of Br. Neither DOMP nor MTC modified significantly blood presure and heart rate in normotensive subjects. Br reduced both systolic and diastolic arterial pressure in hypertensive subjects. The peak of antihypertensive effect appeared 3 hours after drug administration, but reduction of arterial pressure lasted aproximately 6 hours. At the same time Br reduced plasma aldosterone levels and plasma renin activity. MTC and DOMP reversed the antihypertensive effct or Br and its effect on aldosterone levels and plasma renin activity. We conclude from these findings that Br acts as an antihypertensive agent at peripheral and central levels by stimulating DA2 receptors, which are involved in the aldosterone and renin secretion