Premium
Acute hemodynamic and humoral effects of metoclopramide on blood pressure control improvement in subjects with diabetic orthostatic hypotension
Author(s) -
Bessa Angela M,
Zanella M Teresa,
Saragoça Manoel A,
Mulinari Roǵerio A,
Czepielewski Mauro,
Ribeiro Artur B,
Ramos Oswaldo L
Publication year - 1984
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1038/clpt.1984.251
Subject(s) - orthostatic vital signs , plasma renin activity , supine position , medicine , blood pressure , heart rate , hemodynamics , vascular resistance , cold pressor test , mean arterial pressure , anesthesia , tilt (camera) , endocrinology , renin–angiotensin system , mechanical engineering , engineering
Metoclopramide (MCP), a dopaminergic antagonist, is effective in postural hypotension, but the mechanisms of action have not been well defined. We studied responses of mean arterial pressure (MAP), heart rate, cardiac output (CO), and total peripheral resistance (TPR) after 5 min of increasing degrees of head tilt (15° to 90°) before and after MCP (20 mg IV) in seven subjects with diabetic postural hypotension. Plasma renin activity (PRA) and plasma aldosterone levels (PA) were determined at each degree of tilt; responses to the cold pressor test were also assessed before and after MCP. Before MCP, the maximal degree of tilt tolerated was 75°, while after MCP four subjects were able to support 90° tilt. At 45° tilt, the decreases in MAP were smaller after than before MCP (−7.6 ± 3.3 and −28.1 ± 8.5 mm Hg; X ± SE). This was associated with responses of TPR to tilt after (from 18.6 ± 2.6 to 24.0 ± 3.9 arbitrary units [AU]) but not before (from 22.9 ± 4.0 to 25.6 ± 4.5 AU) MCP. Reductions in CO were of the same order before and after MCP. PRA responded to tilt better after than before MCP. Supine PA levels increased with MCP (Δ PA = 5.4 ± 0.7 ng/dl), but its response to tilt was unaltered. There were significant rises in MAP and HR during the cold pressor test after but not before MCP. Our data suggest that vasoconstriction is the main mechanism of MCP improvement in blood pressure response to an orthostatic stimulus in diabetic postural hypotension, possibly because of its antidopaminergic property. Clinical Pharmacology and Therapeutics (1984) 36 , 738–744; doi: 10.1038/clpt.1984.251