Amlodipine Initial Dose in the Elderly
Start amlodipine at 2.5 mg once daily in elderly patients, which is half the standard adult dose of 5 mg. This lower starting dose accounts for the 40-60% increase in drug exposure that occurs in elderly patients due to decreased clearance 1.
FDA-Approved Dosing for Elderly Patients
- The FDA label explicitly recommends 2.5 mg once daily as the initial dose for elderly patients with hypertension, with subsequent titration based on blood pressure response 1.
- Elderly patients experience significantly decreased clearance of amlodipine, resulting in approximately 40-60% higher drug exposure (AUC) compared to younger patients 1.
- The elimination half-life is prolonged in elderly patients (64 hours) compared to younger patients (48 hours) 2.
Titration Strategy
- Wait 7 to 14 days between dose adjustments to allow for steady-state plasma levels, which are reached after 7-8 days of consecutive daily dosing 1.
- The maximum dose is 10 mg once daily, though most elderly patients achieve adequate blood pressure control at lower doses 1.
- More rapid titration may be appropriate if clinically warranted, provided the patient is assessed frequently 1.
Clinical Evidence Supporting Low-Dose Initiation
- Amlodipine 2.5 mg daily demonstrated significant efficacy in elderly hypertensive patients (mean age 66 years), reducing office blood pressure by 12/9 mmHg and 24-hour ambulatory blood pressure by 12/7 mmHg over 12 weeks 3.
- In a large study of over 1,500 elderly patients (≥65 years), amlodipine achieved blood pressure reductions of 25/16 mmHg in those ≥65 years and 26/17 mmHg in those ≥75 years, with treatment success rates exceeding 84% 4.
- The lower starting dose minimizes adverse events while maintaining efficacy, with adverse event rates of 22-24% in elderly patients, comparable to younger populations 4.
Special Considerations for Elderly Patients
- Monitor for orthostatic hypotension by measuring blood pressure in both sitting and standing positions, as elderly patients are at increased risk 5.
- The 2007 European Society of Hypertension guidelines emphasize that initial doses and subsequent titration should be more gradual in elderly patients due to greater risk of adverse effects, particularly in very old and frail subjects 6.
- Amlodipine is particularly effective for isolated systolic hypertension, which is common in elderly patients, producing greater SBP reductions in this population 7, 8.
Dosing Flexibility and Administration
- Amlodipine can be administered at any convenient time of day (morning or evening) to improve adherence, though morning dosing may confer a slight advantage 9, 4.
- For elderly patients with hepatic insufficiency, the 2.5 mg starting dose is especially important as these patients also experience decreased clearance 1.
- No dose adjustment is needed for renal impairment, as amlodipine pharmacokinetics are not significantly influenced by renal function 1.
Common Pitfalls to Avoid
- Do not start at the standard 5 mg dose in elderly patients, as this increases the risk of adverse effects without improving efficacy 1.
- Avoid combining amlodipine with beta-blockers initially without careful monitoring, as they may act synergistically to depress cardiac function 6.
- Peripheral edema is the most common side effect (along with headache, flushing, and constipation), and starting at 2.5 mg helps minimize this 9.