Drug Guide
Enalapril Maleate and Hydrochlorothiazide
Classification
Therapeutic: Antihypertensive
Pharmacological: ACE inhibitor and Thiazide diuretic
FDA Approved Indications
- Hypertension
- Heart failure (off-label)
Mechanism of Action
Enalapril inhibits angiotensin-converting enzyme (ACE), lowering angiotensin II levels, leading to vasodilation and reduced blood pressure; Hydrochlorothiazide inhibits sodium reabsorption in the distal tubules of the kidney, promoting diuresis and lowering blood pressure.
Dosage and Administration
Adult: Typically, 1 tablet once daily, dosage adjusted based on response.
Pediatric: Not approved for pediatric use.
Geriatric: Start at lower doses due to increased sensitivity and renal function decline.
Renal Impairment: Adjust dosage based on renal function, monitor closely.
Hepatic Impairment: Use with caution; no specific dosage adjustment noted.
Pharmacokinetics
Absorption: Both drugs are well absorbed orally.
Distribution: Predominantly bound to plasma proteins.
Metabolism: Enalapril is converted to enalaprilat in the liver; hydrochlorothiazide minimally metabolized.
Excretion: Renally excreted; enalaprilat retains activity; hydrochlorothiazide excreted unchanged.
Half Life: Enalapril: approx. 11 hours; Hydrochlorothiazide: approx. 6-15 hours.
Contraindications
- History of angioedema related to previous ACE inhibitor therapy
- Hypersensitivity to enalapril, hydrochlorothiazide, or sulfonamide-derived drugs
- Bilaterally renal artery stenosis
Precautions
- Pregnancy (especially second and third trimester), lactation, renal impairment, electrolyte disturbances, volume depletion
Adverse Reactions - Common
- Dizziness (common)
- Hyperkalemia (common)
- Hypotension (common)
Adverse Reactions - Serious
- Angioedema (rare)
- Progressive renal impairment (rare)
- Severe hypotension (rare)
Drug-Drug Interactions
- Potassium-sparing diuretics, Aldosterone antagonists, Other antihypertensives, Lithium
Drug-Food Interactions
- High potassium foods (may increase hyperkalemia)
Drug-Herb Interactions
- St. John's Wort (may affect blood pressure)
Nursing Implications
Assessment: Monitor blood pressure, renal function, serum electrolytes, signs of angioedema.
Diagnoses:
- Ineffective tissue perfusion related to hypotension or edema.
- Electrolyte imbalance.
Implementation: Administer as prescribed, monitor vital signs and labs, educate patient on signs of adverse effects.
Evaluation: Assess blood pressure response, renal function, electrolytes, and patient adherence.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Report signs of angioedema, hyperkalemia, or severe dizziness.
- Avoid potassium supplements and high-potassium foods unless directed.
- Stand up slowly to minimize orthostatic hypotension.
Special Considerations
Black Box Warnings:
- Fetal toxicity—discontinue as soon as pregnancy is detected.
Genetic Factors: Caution in individuals with genetic predispositions to angioedema.
Lab Test Interference: May increase serum creatinine and potassium.
Overdose Management
Signs/Symptoms: Severe hypotension, electrolyte disturbances.
Treatment: Administer intravenous fluids, vasopressors if needed, monitor electrolytes, and support vitals as necessary.
Storage and Handling
Storage: Store at room temperature, 15–30°C (59–86°F).
Stability: Stable for shelf life when stored properly.