Hemodynamic and metabolic effects of intravenous clentiazem in hypertensive patients.
To determine the hemodynamic and certain metabolic effects of clentiazem, a diltiazem congener, 10 untreated essential hypertensive patients were given the calcium antagonist in 3 successive doses totaling 1.0 mg/kg intravenously. Mean arterial pressure and total peripheral resistance progressively declined from 121 +/- 3 mm Hg and 47 +/- 2 U (mean) to 110 +/- 3 mm Hg and 33 +/- 1 U, respectively (p less than 0.05); heart rate remained unchanged. Cardiac output increased as a result of augmented cardiopulmonary volume (p less than 0.05) produced by peripheral venoconstriction and norepinephrine release (from 258 +/- 41 to 319 +/- 42 pg/ml; p less than 0.01). Surprisingly, there was an immediate reduction in plasma aldosterone (10.4 +/- 1.2 to 6.5 +/- 1.0 ng/dl; p less than 0.01), serum potassium (4.3 +/- 0.1 to 3.6 +/- 0.1 mEq/dl; p less than 0.001) and calcium (9.5 +/- 0.1 to 8.8 +/- 0.1 mg/dl; p less than 0.001) concentrations, whereas epinephrine increased (21.2 +/- 3.3 to 45.8 +/- 5.9 pg/ml; p less than 0.002). Previous studies with diltiazem, conducted similarly, did not show these changes. Therefore, clentiazem reduced mean arterial pressure through a decrease in total peripheral resistance, and released epinephrine was associated with intracellular potassium influx (urinary potassium did not change). The inhibited aldosterone release was not compensated by altered renal blood flow, glomerular filtration or increased plasma renin activity. These findings underscore the concept that calcium antagonists are a remarkably heterogeneous antihypertensive group.
Frohlich
E D
ED
Department of Internal Medicine, Ochsner Clinic, New Orleans, Louisiana.
McLoughlin
M
M
Ketelhut
R
R
D000368:Aged; D000704:Analysis of Variance; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000627:therapeutic use*; D004110:Diltiazem / Q000031:analogs & derivatives* / Q000627:therapeutic use; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D014655:Vascular Resistance / Q000187:drug effects
D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; C056595:clentiazem; D004110:Diltiazem