Nurses Compass
Drug Guide
Amlodipine Maleate
Classification
Therapeutic: Antihypertensive, Antianginal
Pharmacological: Calcium channel blocker, dihydropyridine
FDA Approved Indications
- Chronic stable angina
- Varying forms of hypertension
Mechanism of Action
Amlodipine inhibits calcium ion influx across cell membranes in vascular smooth muscle and cardiac muscle, resulting in vasodilation and reduced peripheral resistance, which decreases blood pressure and myocardial oxygen demand.
Dosage and Administration
Adult: Initial dose typically 5 mg once daily; may be titrated up to 10 mg once daily based on response.
Pediatric: Not approved for pediatric hypertension or angina.
Geriatric: Start at lower dose (e.g., 2.5 mg) and titrate cautiously.
Renal Impairment: Use with caution; no specific adjustment needed but monitor closely.
Hepatic Impairment: Initial dose of 2.5 mg is recommended; titrate cautiously.
Pharmacokinetics
Absorption: Well absorbed after oral administration.
Distribution: Widely distributed; protein binding approximately 97%.
Metabolism: Extensively metabolized in the liver via CYP3A4.
Excretion: Primarily eliminated via urine and feces; metabolites predominantly excreted in urine.
Half Life: 30 to 50 hours, allowing once-daily dosing.
Contraindications
- Hypersensitivity to amlodipine or other dihydropyridines.
- Severe aortic stenosis.
Precautions
- Use cautiously in cases of severe hepatic impairment.
- Monitor for hypotension, especially in volume-depleted patients.
Adverse Reactions - Common
- Edema (pedal) (Common)
- Headache (Common)
- Dizziness (Common)
- Flushing (Common)
Adverse Reactions - Serious
- Hypotension (Uncommon)
- Palpitations or tachycardia (Uncommon)
- Myocardial ischemia (in cases of excessive vasodilation) (Rare)
Drug-Drug Interactions
- Simvastatin (increased risk of myopathy)
- Beta-blockers (combine cautiously due to potential for excessive hypotension)
- Grapefruit juice (may increase plasma levels)
Drug-Food Interactions
N/ADrug-Herb Interactions
N/ANursing Implications
Assessment: Monitor blood pressure and heart rate before and after administration.
Diagnoses:
- Risk for hypotension
- Ineffective tissue perfusion related to vasodilation.
Implementation: Administer consistently at the same time daily. Monitor for adverse reactions and efficacy.
Evaluation: Assess blood pressure regularly; evaluate for signs of adverse effects.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Do not discontinue abruptly, especially if on antihypertensive therapy.
- Notify healthcare provider of swelling, chest pain, or adverse reactions.
- Limit alcohol intake and avoid grapefruit juice.
- Rise slowly from sitting or lying position to minimize dizziness.
Special Considerations
Black Box Warnings: N/A
Genetic Factors: Genetic polymorphisms in CYP3A4 can affect metabolism.
Lab Test Interference: Rare; monitor liver function in long-term use.
Overdose Management
Signs/Symptoms: Severe hypotension, tachycardia, arrhythmias, or dizziness.
Treatment: Supportive care including IV fluids or vasopressors; calcium gluconate may be used as an antidote in severe cases.
Storage and Handling
Storage: Store at room temperature (20-25°C).
Stability: Stable until the expiration date on the package.