Enalaprilat
Active metabolite of enalapril and intravenous ACE inhibitor for hypertensive emergencies and heart failure.
Chemical Identity
| Property | Value |
|---|---|
| Chemical Formula | C18H24N2O5 |
| Molecular Weight | 348.4 Da |
| CAS Number | 76420-72-9 |
| Peptide Class | Dipeptide Derivative (ACE Inhibitor) |
| Route | IV |
Structure
Enalaprilat is the active dicarboxylic acid metabolite of the prodrug enalapril. It contains a tripeptide-mimetic structure with a carboxylate group that binds the zinc ion in the ACE active site. Unlike enalapril, enalaprilat is highly hydrophilic and poorly absorbed orally.
Mechanism of Action
Enalaprilat competitively inhibits angiotensin-converting enzyme (ACE, kininase II), blocking conversion of angiotensin I to angiotensin II and reducing aldosterone secretion. This decreases vasoconstriction, sodium retention, and sympathetic activation. It also inhibits bradykinin degradation, contributing to vasodilation.
Clinical Applications
- Hypertensive emergencies: IV antihypertensive when oral therapy not feasible
- Heart failure: Acute decompensated heart failure
- Post-operative hypertension: ICU blood pressure management
- Enalapril equivalent: For patients unable to take oral medications
Pharmacokinetics
- Half-life: 11 hours
- Onset: 15 minutes (IV)
- Duration: 6-24 hours
- Metabolism: Active form (enalapril is prodrug)
- Elimination: Renal
- Route: IV bolus or infusion
Safety and Side Effects
Hypotension (first-dose, especially volume-depleted patients), hyperkalemia, renal impairment, angioedema (rare), and cough. Contraindicated in bilateral renal artery stenosis and pregnancy.
References
- DiPette, D.J., et al. (1986). Enalaprilat for hypertensive emergencies. American Journal of Medicine, 81, 48-52.
- Hirschl, M.M., et al. (1993). Enalaprilat versus sodium nitroprusside. American Journal of Hypertension, 6, 62S-66S.
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