Efficacy, electrocardiographic and renal effects of intravenous diltiazem for essential hypertension.

The acute systemic blood pressure, electrocardiographic and renal function responses to an intravenous bolus infusion of diltiazem (0.2 to 0.5 mg/kg) were evaluated in 18 subjects with mild to moderate essential hypertension. Although a significant blood pressure response occurred within 5 minutes, blood pressure returned to pretreatment levels within 1 to 3 hours. After drug infusion, a variety of rhythm and conduction disturbances were noted; the most important were transient prolongation of the PR Interval (first-degree atrioventricular block), a single episode of second-degree atrioventricular block (Mobitz I) associated with T-wave inversion and a transient episode of junctional escape rhythm and atrioventricular dissociation. Intravenous diltiazem had no consistent effect on glomerular filtration rate or effective renal plasma flow. Natriuresis and kaliuresis were observed only at the highest infusion dose. It is concluded that an alternative dosing regimen will be required if intravenous diltiazem is to be used safely and effectively to control blood pressure in patients with hypertensive disease.