enalaprilat-anhydrous and Tachycardia

We compared the efficacy of the combination of enalaprilat/labetalol with that of enalaprilat/nicardipine to prevent emergence postcraniotomy hypertension. A prospective, randomized open labeled clinical trial was designed to compare the incidence of breakthrough hypertension (systolic blood pressure [SBP] > 140 mm Hg) and adverse effects (hypotension, tachycardia, and bradycardia) between the two drug combinations. Secondarily, the effects of the drugs on SBP, mean blood pressure, and diastolic blood pressure were evaluated over the course of the study. Forty-two patients received enalaprilat 1.25 mg IV at dural closure followed by either multidose nicardipine 2 mg IV or labetalol 5 mg IV to maintain the SBP below 140 mm Hg. SBP was similarly controlled in both groups. There was a marginally smaller incidence of failures and adverse effects with labetalol. Blood pressure profiles were similar for both groups.

Topics: Adrenergic alpha-Antagonists; Adrenergic beta-Antagonists; Adult; Aged; Analysis of Variance; Anesthesia Recovery Period; Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Blood Pressure; Bradycardia; Brain Neoplasms; Calcium Channel Blockers; Chi-Square Distribution; Craniotomy; Enalaprilat; Female; Humans; Hypertension; Hypotension; Incidence; Labetalol; Male; Middle Aged; Nicardipine; Prospective Studies; Tachycardia; Treatment Outcome

Coronary flow reserve is reduced in patients with idiopathic dilated cardiomyopathy (DCM). We examined acute effects of intracoronary enalaprilat on metabolic coronary vasodilation during pacing tachycardia in patients. Coronary blood flow (Doppler guidewire) and diameter (quantitative angiography) were measured in seven patients with DCM and seven control subjects. In the DCM group, tachypacing increased coronary blood flow by 37 +/- 22% from the baseline before enalaprilat and by 65 +/- 22% (p < 0.01 vs. before treatment) after enalaprilat (0.5 microg/kg/min for 5 min, i.c.) at comparable double product. Pacing-induced dilation of the epicardial coronary artery also was greater after enalaprilat (p < 0.05). Effects of enalaprilat on coronary blood flow and diameter during pacing tachycardia were abolished by pretreatment with intracoronary administration of the nitric oxide (NO) synthesis inhibitor, N(G)-monomethyl-L-arginine. These beneficial effects of enalaprilat on large and small coronary vasodilation were not observed in control patients. Thus, intracoronary enalaprilat acutely augmented dilator responses of the large and small coronary arteries to pacing tachycardia in patients with DCM, and NO appeared to play an important role in mediating the effects of enalaprilat. These favorable effects of enalaprilat on the coronary circulation may be of clinical significance in patients with heart failure due to nonischemic DCM. Further long-term studies of the effects of angiotensin-converting enzyme inhibition on coronary vasodilation will be needed in this population.

Topics: Aged; Angiotensin-Converting Enzyme Inhibitors; Cardiomyopathy, Dilated; Coronary Vessels; Drug Interactions; Enalaprilat; Enzyme Inhibitors; Female; Hemodynamics; Humans; Infusions, Intra-Arterial; Male; Middle Aged; Nitric Oxide; omega-N-Methylarginine; Tachycardia; Vasodilation; Vasodilator Agents