Nurses Compass
Drug Guide
Amlodipine Besylate and Benazepril Hydrochloride
Classification
Therapeutic: Antihypertensive
Pharmacological: Calcium channel blocker and ACE inhibitor combination
FDA Approved Indications
- Hypertension (high blood pressure)
Mechanism of Action
Amlodipine is a calcium channel blocker that decreases vascular resistance and blood pressure by inhibiting calcium influx into vascular smooth muscle and myocardium. Benazepril is an angiotensin-converting enzyme (ACE) inhibitor that lowers blood pressure by inhibiting the formation of angiotensin II, leading to vasodilation and decreased aldosterone secretion.
Dosage and Administration
Adult: Typically 5 mg once daily, titratable up to 10 mg based on response.
Pediatric: Not approved for pediatric use.
Geriatric: Initial dose may be lower; closely monitor due to increased sensitivity.
Renal Impairment: Adjust dosage based on renal function; monitor blood pressure and renal parameters.
Hepatic Impairment: Use caution; monitor for adverse effects; dose adjustments may be necessary.
Pharmacokinetics
Absorption: Well absorbed orally.
Distribution: Protein binding of amlodipine approximately 93%; benazepril approximately 95%.
Metabolism: Amlodipine is primarily metabolized in the liver; benazepril is a prodrug converted to benazeprilat in the liver.
Excretion: Amlodipine is excreted mainly via hepatic metabolism; benazeprilat is eliminated renally.
Half Life: Amlodipine approximately 30-50 hours; benazeprilat approximately 10-11 hours.
Contraindications
- Hypersensitivity to amlodipine, benazepril, or other ACE inhibitors.
- History of angioedema related to previous ACE inhibitor therapy.
Precautions
- Use with caution in patients with aortic stenosis, renal artery stenosis, or intravascular volume depletion.
- Pregnancy Category D; contraindicated in pregnancy due to risk of fetal injury or death.
- Monitor blood pressure, renal function, and serum potassium regularly during therapy.
Adverse Reactions - Common
- Swelling of the face, lips, tongue, or throat (angioedema) (Less than 1%)
- Dizziness or lightheadedness, especially after the first dose (Common)
- Cough (Common)
Adverse Reactions - Serious
- Angioedema requiring medical attention (Rare)
- Hypotension, especially in volume-depleted patients (Rare)
- Elevated serum potassium (hyperkalemia) (Rare)
Drug-Drug Interactions
- Other antihypertensives, diuretics, potassium-sparing agents, lithium, aliskiren.
Drug-Food Interactions
- Foods high in potassium, salt substitutes containing potassium.
Drug-Herb Interactions
- Potential interactions with herbal products that affect blood pressure or potassium levels, such as Ginseng or St. John's Wort.
Nursing Implications
Assessment: Monitor blood pressure, renal function, and serum electrolytes before and during therapy.
Diagnoses:
- Risk for hypotension, risk for decreased cardiac output.
Implementation: Administer as prescribed, typically once daily. Educate patients on the importance of adherence and monitoring symptoms.
Evaluation: Assess for blood pressure control and adverse effects; adjust dosage as needed.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Do not discontinue abruptly.
- Report signs of angioedema, persistent cough, or hyperkalemia.
- Avoid potassium-rich foods or supplements unless directed.
Special Considerations
Black Box Warnings:
- Fetal toxicity; contraindicated during pregnancy.
Genetic Factors: Patients with a history of angioedema may be at increased risk.
Lab Test Interference: May elevate serum potassium and serum creatinine.
Overdose Management
Signs/Symptoms: Severe hypotension, dizziness, tachycardia or bradycardia.
Treatment: Supportive care with intravenous fluids; vasopressors for hypotension; calcium gluconate for calcium channel blocker overdose; dialysis in severe cases.
Storage and Handling
Storage: Store at room temperature, 20-25°C (68-77°F).
Stability: Stable under recommended storage conditions.