What it's for (Indications)
- Amlodipine is indicated for the management of hypertension, either as monotherapy or in combination with other antihypertensive agents.
- Its efficacy in reducing blood pressure has been consistently demonstrated across various patient populations, including adults and pediatric patients aged 6 years and older.
- Furthermore, amlodipine is approved for the symptomatic treatment of chronic stable angina, where it helps to decrease the frequency of anginal episodes and reduce the need for nitroglycerin.
- It is also indicated for the treatment of confirmed or suspected vasospastic angina (Prinzmetal's or variant angina), providing relief by preventing coronary artery spasm.
- These broad indications highlight its versatility and importance in the management of common cardiovascular conditions.
- Its prolonged duration of action supports once-daily dosing, contributing to patient adherence.
Dosage Information
| Type | Guideline |
|---|---|
| Standard | For hypertension and angina, the usual initial oral dosage of amlodipine is 5 mg once daily. The dosage can be adjusted based on the patient's clinical response and tolerability, with a maximum recommended dose of 10 mg once daily. Dosage adjustments should typically occur at intervals of 7 to 14 days to allow for steady-state plasma concentrations to be achieved and to accurately assess the therapeutic effect. For elderly patients or those with hepatic impairment, a lower starting dose of 2.5 mg once daily is generally recommended, with careful and gradual upward titration under close medical supervision due to potentially decreased clearance. Amlodipine can be administered without regard to food. In pediatric patients (6-17 years old) with hypertension, the recommended initial dose is 2.5 mg once daily, with titration up to 5 mg once daily based on response. |
Safety & Warnings
Common Side Effects
- Amlodipine is generally well-tolerated, but like all medications, it can cause a range of adverse effects.
- The most commonly reported side effect is peripheral edema (swelling of the ankles and feet), which is dose-dependent and can occur in a significant percentage of patients, particularly at higher doses.
- Other frequent adverse reactions include headache, flushing, fatigue, dizziness, palpitations, and nausea.
- Less common side effects may involve abdominal pain, somnolence, dyspepsia, pruritus, muscle cramps, and visual disturbances.
- More serious, though rare, adverse events include hypotension, syncope, exacerbation of angina or acute myocardial infarction (particularly upon initiation or dose increase in patients with severe obstructive coronary artery disease), and hepatic enzyme elevations.
- Patients should be advised to promptly report any new or worsening symptoms to their healthcare provider for evaluation.
Serious Warnings
- Black Box Warning: Amlodipine does not carry an FDA-mandated Black Box Warning. However, healthcare professionals and patients should be acutely aware of several serious clinical considerations that warrant careful monitoring and appropriate management. These include the potential for symptomatic hypotension, especially during the initiation of therapy or dose titration, which may be more pronounced in patients with severe aortic stenosis. There is a rare but documented risk of worsening angina or acute myocardial infarction upon initiation or dose increase of calcium channel blockers, including amlodipine, particularly in patients with severe obstructive coronary artery disease. Amlodipine should be used with caution in patients with heart failure due to the risk of peripheral edema, which can complicate heart failure management. Patients with impaired hepatic function may require a lower starting dose and careful titration due to reduced drug clearance. These warnings underscore the importance of individualized dosing and vigilant patient monitoring.
- Amlodipine, while generally well-tolerated, requires careful consideration regarding several serious warnings and precautions.
- Patients may experience symptomatic hypotension, especially upon initiation of therapy or during dose titration.
- This risk is elevated in patients with severe aortic stenosis or those who are volume-depleted.
- There have been rare reports of increased frequency, duration, or severity of angina or acute myocardial infarction occurring upon initiation or dosage increase of calcium channel blockers, including amlodipine, particularly in patients with severe obstructive coronary artery disease.
- Amlodipine should be used with caution in patients with heart failure.
- While studies in NYHA Class II-IV heart failure patients showed no adverse effect on survival, peripheral edema, a common side effect, can be difficult to distinguish from worsening heart failure.
- Patients with impaired hepatic function may have reduced clearance of amlodipine, necessitating a lower starting dose and careful titration.
- Close monitoring for adverse effects is crucial in these vulnerable populations.
How it Works (Mechanism of Action)
Amlodipine is a dihydropyridine calcium channel blocker that functions by selectively inhibiting the transmembrane influx of calcium ions into vascular smooth muscle cells and cardiac muscle cells. Its primary mechanism in treating hypertension involves directly relaxing vascular smooth muscle, leading to a significant reduction in peripheral vascular resistance and, consequently, a decrease in systemic blood pressure. In the context of angina, amlodipine reduces myocardial oxygen demand by decreasing total peripheral resistance (afterload) against which the heart must pump. Furthermore, it dilates coronary arteries and arterioles, both in normal and ischemic regions, thereby increasing myocardial oxygen delivery. This effect is particularly beneficial in patients with vasospastic (Prinzmetal's or variant) angina by preventing coronary artery spasm. The relatively slow onset of action and prolonged elimination half-life contribute to its sustained therapeutic effect and once-daily dosing regimen.