ACTIONS AND PHARMACOLOGY This agent, which is the first intravenous ACE inhibitor approved for clinical use, is the biologically active form of the oral ACE inhibitor enalapril that occurs after deesterification in the liver. It is effective in patients with chronic heart failure with left ventricular ejection fractions of 20 to 44 percent, because it causes coronary vasodilation and significant reduction in mean arterial blood pressure and pulmonary capillary wedge pressure. It also improves cardiac index and stroke volume without affecting the heart rate or stroke work index.18
The onset of antihypertensive effect is within minutes of an intravenous bolus injection, with the maximal decrease in DBP in 30 min and duration of action up to 6 h. The degree of blood pressure reduction seems to be associated with the degree of pretreatment plasma renin activity, thus suggesting that the mechanism of antihypertensive effect may be renin-angiotensin inhibition.18 Enalaprilat is excreted primarily by the kidney; therefore, its dosage should be decreased in patients with severe renal insufficiency.
INDICATIONS Enalaprilat is an effective intravenous antihypertensive agent in hypertensive emergencies that can be easily replaced by oral enalapril for long-term maintenance therapy.
USE An initial dose of 0.625 to 1.25 mg by intravenous bolus has been found to be effective in reducing blood pressure and heart rate. Doses of 2.5, 5, and 10 mg, up to a maximum of 40 mg, have been tried in different studies but have not been found to show appreciable difference in the magnitude of blood pressure reduction with increasing dose.23 A bolus can be given every 6 h. The onset of hypotensive effects is variable.
SIDE EFFECTS AND CONTRAINDICATIONS This agent produces complications and effects that are similar to those of other ACE inhibitors, most notably angioneurotic edema and deterioration of renal function.
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Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...