Diltiazem in Hypoxic Pulmonary Hypertension

The short-term effects of intravenously administered diltiazem on pulmonary and systemic hemodynamics were evaluated in patients with hypoxic pulmonary hypertension. Twelve patients were randomly assigned to two groups in a double-blind fashion. One group (eight patients) received diltiazem, and the other group (four patients) received a placebo. Three increasing doses of diltiazem (0.2, 0.3, and 0.4 mg/kg of body weight) were injected into each patient, followed each time by an infusion (2�agg6 however, a concomitant fall in cardiac output has been observed, which could be detrimental in the severely hypoxic patient. Nifed- ipine has been shown to decrease hypoxic pulmonary vasoconstriction in patients with respiratory failure7 and in patients with COPD;5 however, beneficial effects ofthis drug are not constant8 and are difficult to predict because no "intravenous test" can be per- formed before oral administration, since nifedipine is not suitable for intravenous use. Diltiazem, which is another calcium antagonist, has been shown to decrease the pulmonary vascular resist- ance in patients with primary pulmonary hyperten- sion9.lo and can be used intravenoulsy; however, to our knowledge, there are no data on the hemodynamic effects ofdiltiazem in patients with hypoxic pulmonary hypertension. Thus, the aims of the present study were to determine if diltiazem decreases the pulmo-