The American journal of cardiology
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Comparative Study
Comparative effects of nifedipine, verapamil, and diltiazem on experimental pulmonary hypertension.
The role of calcium-channel blocking agents in the treatment of pulmonary hypertension is not well defined. Consequently, the effects of diltiazem, nifedipine, and verapamil were compared in 3 groups of anesthetized dogs (n = 6 for each group). In each group, normoxic hemodynamic variables were recorded before and after increasing doses of diltiazem, nifedipine, and verapamil (5 X 10(-8) M/kg, low; 10(-7) M/kg, medium; and 10(-6) M/kg, high dose; given intravenously over 2 minutes). ⋯ This was accompanied by a 157% increase in cardiac output and only a small increase in pulmonary arterial pressure (7 mm Hg). Again, diltiazem produced no change in pulmonary hemodynamic variables. In these acute studies, nifedipine appeared to be a more effective pulmonary vasodilator than verapamil or diltiazem.