Is 2.5mg of amlodipine (Narvasc) an appropriate initial dose for a 93-year-old patient with hypertension?

Amlodipine 2.5mg is Appropriate for a 93-Year-Old Patient

Yes, 2.5mg of amlodipine (Narvasc) is the correct initial dose for a 93-year-old patient with hypertension, as recommended by the FDA for elderly, small, or fragile patients. 1

FDA-Approved Dosing for Elderly Patients

The FDA drug label explicitly states that small, fragile, or elderly patients should be started on 2.5mg once daily 1. This lower starting dose is critical because:

• Elderly patients have 40-60% higher drug exposure (AUC) due to decreased clearance of amlodipine 1
• The elimination half-life is prolonged in elderly patients (64 hours vs. 48 hours in younger patients) 2
• A lower initial dose minimizes the risk of dose-related adverse effects, particularly hypotension and peripheral edema 1

Evidence Supporting 2.5mg in Very Elderly Patients

Research specifically demonstrates that 2.5mg daily is both effective and well-tolerated in elderly hypertensive patients:

• A Brazilian multicenter study in patients aged 66.3 ± 5.3 years showed that 2.5mg daily significantly reduced blood pressure across office, 24-hour ambulatory, and home measurements with infrequent adverse reactions 3
• Elderly patients (65-73 years) achieved significant blood pressure reductions at doses ranging from 2.5-10mg daily, with diastolic pressure decreasing from 100 to 93 mmHg at just 2 weeks on 2.5mg 2

Titration Strategy for This Patient

Start with 2.5mg once daily and titrate cautiously 1:

• Wait 7-14 days between dose adjustments to allow for steady-state accumulation (which takes 1-1.5 weeks due to the 40-60 hour half-life) 1, 4
• Monitor for orthostatic hypotension by measuring blood pressure in both sitting and standing positions 5
• If blood pressure remains uncontrolled after adequate trial, increase to 5mg daily, then to a maximum of 10mg if needed 1

Important Monitoring Parameters

Watch for these specific adverse effects in very elderly patients:

• Peripheral edema (dose-dependent, more common with higher doses) 5, 6
• Orthostatic hypotension and dizziness (measure BP in erect posture at each visit) 5, 6
• Gradual onset of effect occurs over 4-8 hours after dosing, with steady-state achieved after 1-1.5 weeks 4

Clinical Considerations for 93-Year-Old Patients

The 2007 European Society of Hypertension guidelines emphasize that initial doses and subsequent titration should be more gradual in very old and frail subjects due to greater chance of undesirable effects 5. At age 93, this patient likely falls into the "frail elderly" category where:

• 2.5mg is the safest starting point to assess tolerability 1
• Blood pressure goals should be individualized based on frailty status, though the target remains <140/90 mmHg if tolerated 5
• Discontinuation of amlodipine, if needed, results in slow return to baseline over 7-10 days without rebound effect 4

Common Pitfall to Avoid

Do not start at 5mg in a 93-year-old patient despite this being the "usual" adult dose 1. The FDA specifically designates 2.5mg for elderly patients due to pharmacokinetic changes, and starting higher increases the risk of symptomatic hypotension and falls, which carry significant morbidity and mortality risk in nonagenarians 1, 2.