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Measurement of partial agonist activity of pindolol
Author(s) -
Carruthers S George,
TwumBarima Yaw
Publication year - 1981
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.1981.207
Subject(s) - pindolol , partial agonist , metoprolol , agonist , heart rate , practolol , pharmacology , chemistry , intrinsic activity , medicine , oxprenolol , endocrinology , receptor , blood pressure , propranolol
The partial agonist activity of pindolol was assessed by examining the action of cumulative doses on the heart rates of resting, standing, and exercising healthy men and by studying the interaction of pindolol with metoprolol, a beta blocker devoid of partial agonist activity. Pindolol did not affect resting or standing heart rates (RHR, SHR) but reduced the heart rate after vigorous exercise by approximately 25%. The flatter dose‐response curve of pindolol for exercise heart rate (EHR) has been reported for practolol and oxprenolol, which also exert partial agonist activity. After extremely large doses of pindolol there was no evidence of enhancement of agonist activity on RHR, nor was there any evidence of dominance of agonist activity over antagonist activity on EHR. Metoprolol did not alter RHR but reduced SHR by approximately 20% and EHR bx approximately 31%. The effects of pindolol on SHRs and EHRs were not enhanced by metoprolol, even though the drug bx itself induced greater reductions of both. The reduction of SHR bx metoprolol was reversed by pindolol. Pindolol appears to have greater affinity than metoprolol for atrial beta adrenoceptors in man. Clinical Pharmacology and Therapeutics (1981) 30, 581–586; doi: 10.1038/clpt.1981.207