Histamine antagonists and d-tubocurarine-induced hypotension in cardiac surgical patients.
Hemodynamic effects and histamine release by bolus injection of 0.35 mg/kg of d-tubocurarine were studied in 24 patients. H1- and H2-histamine antagonists or placebo were given before dosing with d-tubocurarine in a randomized double-blind fashion to four groups: group 1--placebo; group 2--cimetidine, 4 mg/kg, plus placebo; group 3--chlorpheniramine, 0.1 mg/kg, plus placebo; and group 4--cimetidine plus chlorpheniramine. Histamine release occurred in most patients, the highest level 2 minutes after d-tubocurarine dosing. Group 1 had a moderate negative correlation between plasma histamine change and systemic vascular resistance (r = 0.58; P less than 0.05) not present in group 4. Prior dosing with antagonists partially prevented the fall in systemic vascular resistance. These data demonstrate that the hemodynamic changes associated with d-tubocurarine dosing are only partially explained by histamine release. Thus prior dosing with H1- and H2-antagonists provides only partial protection.
D001794:Blood Pressure / Q000187:drug effects; D002744:Chlorpheniramine / Q000494:pharmacology; D002927:Cimetidine / Q000494:pharmacology; D002986:Clinical Trials as Topic; D001026:Coronary Artery Bypass; D004311:Double-Blind Method; D004338:Drug Combinations; D006633:Histamine Antagonists / Q000494:pharmacology*; D006636:Histamine Release / Q000187:drug effects; D006801:Humans; D007022:Hypotension / Q000209:etiology*; D011897:Random Allocation; D014403:Tubocurarine / Q000494:pharmacology*; D014655:Vascular Resistance / Q000187:drug effects
D004338:Drug Combinations; D006633:Histamine Antagonists; D002744:Chlorpheniramine; D002927:Cimetidine; D014403:Tubocurarine