Generic Name

Hydrochlorothiazide; Lisinopril

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Classification

FDA Approved Indications

• Hypertension
• Heart failure (off-label)

Mechanism of Action

Lisinopril inhibits angiotensin-converting enzyme (ACE), reducing angiotensin II formation, leading to vasodilation and decreased aldosterone secretion. Hydrochlorothiazide inhibits sodium reabsorption in the distal tubules of the nephron, promoting diuresis and reducing blood volume.

Dosage and Administration

Adult: Typically, 10-20 mg of lisinopril once daily combined with 12.5-25 mg of hydrochlorothiazide once daily, titrated based on response.

Pediatric: Not generally recommended for children; consult specific guidelines.

Geriatric: Start at lower doses due to increased sensitivity and risk of adverse effects.

Renal Impairment: Dose adjustment required; contraindicated in severe impairment.

Hepatic Impairment: Use with caution; monitor closely.

Pharmacokinetics

Absorption: Well absorbed orally

Distribution: Lisinopril is not significantly bound to plasma proteins; hydrochlorothiazide binds to plasma proteins to some extent.

Metabolism: Lisinopril is not metabolized extensively; hydrochlorothiazide undergoes minimal metabolism.

Excretion: Lisinopril is excreted unchanged by the kidneys; hydrochlorothiazide is mainly excreted unchanged in urine.

Half Life: Lisinopril: approximately 12 hours; hydrochlorothiazide: approximately 6-15 hours.

Contraindications

• History of hypersensitivity to ACE inhibitors or sulfonamide-derived medications.
• Angioedema related to previous ACE inhibitor therapy.
• Bilateral renal artery stenosis.

Precautions

• Pregnancy (category D), lactation.
• Renal impairment.
• Hypovolemia and hypotension.
• Monitor serum K+ and renal function regularly.

Adverse Reactions - Common

• Dizziness (Common)
• Hypokalemia or Hyperkalemia (Common)
• Cough (ACE inhibitor related) (Common)
• Orthostatic hypotension (Common)

Adverse Reactions - Serious

• Angioedema (Serious, rare)
• Acute renal failure (Rare)
• Anaphylactoid reactions (Rare)

Drug-Drug Interactions

• Potassium supplements, potassium-sparing diuretics, other antihypertensives, NSAIDs
• Lithium

Drug-Food Interactions

• High potassium foods (e.g., bananas, oranges) that may increase hyperkalemia risk

Drug-Herb Interactions

N/A

Nursing Implications

Patient/Family Teaching

• Take medication exactly as prescribed.
• Report signs of angioedema, persistent cough, or hyperkalemia.
• Avoid potassium-rich foods and potassium supplements unless directed.
• Change positions slowly to minimize dizziness.

Special Considerations

Black Box Warnings:

• Fetal toxicity if used during pregnancy.
• Angioedema risk related to ACE inhibitors.

Genetic Factors: Genetic variations may affect ACE inhibitor metabolism and response.

Lab Test Interference: ACE inhibitors can increase serum potassium and affect renal function tests.

Overdose Management

Signs/Symptoms: Severe hypotension, dizziness, electrolyte disturbances, renal impairment.

Treatment: Discontinue drug, provide supportive care, administer intravenous fluids and electrolytes as needed, vasopressors if hypotension persists.

Storage and Handling

Storage: Store at room temperature, 15-30°C.

Stability: Stable under recommended storage conditions.