What side effects should I warn an elderly patient with hypertension or coronary artery disease about when starting amlodipine (calcium channel blocker) at a low dose of 5mg?

Key Side Effects to Warn About When Starting Amlodipine 5mg

The most important side effect to warn your patient about is peripheral edema (ankle/leg swelling), which occurs in approximately 10-14% of patients and is the most common reason for discontinuation. 1, 2, 3

Most Common Side Effects

Peripheral Edema

• Ankle and leg swelling occurs in 10.5-13.8% of patients on amlodipine, making it the most frequent adverse effect 2, 3
• This edema is dose-dependent and results from preferential arteriolar vasodilation causing increased capillary hydrostatic pressure, not from fluid retention 1
• The gradual onset of action with amlodipine (peak effect at 6-12 hours) means edema typically develops over days to weeks rather than acutely 1
• Reassure patients this is not dangerous and does not indicate heart or kidney problems, but they should report it if bothersome as dose reduction or medication change may be needed 3

Headache

• Headache occurs in 2-7.8% of patients, typically mild and transient, resolving within the first few weeks of treatment 2, 3
• Unlike other dihydropyridines, amlodipine's gradual onset significantly reduces the incidence of vasodilatory headaches compared to agents like nitrendipine 4

Other Vasodilatory Effects

• Flushing and dizziness are uncommon with amlodipine (much lower than other dihydropyridines) due to its gradual onset of action 4
• The 30-50 hour half-life and slow absorption prevent the rapid vasodilation that causes these symptoms with shorter-acting calcium channel blockers 1, 4

Cardiovascular Considerations

Blood Pressure Effects

• Symptomatic hypotension is possible but unlikely due to the gradual onset of action—acute hypotension is rare even at therapeutic doses 1
• In elderly patients, monitor for orthostatic hypotension and falls, as they have 40-60% higher drug exposure due to decreased hepatic clearance 5, 1
• The 5mg starting dose is appropriate and reduces risk of excessive blood pressure lowering 5

Paradoxical Angina (If Patient Has Coronary Disease)

• Warn patients with known coronary artery disease that worsening angina or even myocardial infarction can occur when starting or increasing amlodipine dose, particularly in severe obstructive coronary disease 1
• This is uncommon but serious—instruct patients to report any new or worsening chest pain immediately 1

Heart Rate

• Amlodipine does not significantly alter heart rate at rest, though slight increases (not clinically significant) may occur 6 hours post-dose 6
• Unlike non-dihydropyridine calcium channel blockers (diltiazem, verapamil), amlodipine does not cause bradycardia or heart block 1

What NOT to Worry About

Metabolic and Laboratory Parameters

• Amlodipine does not adversely affect cholesterol, triglycerides, glucose, or electrolytes—no routine laboratory monitoring is required 4
• No significant effects on hematologic parameters have been observed 4

Cardiac Conduction

• Amlodipine does not alter cardiac electrical conduction—no risk of heart block or arrhythmias, even when combined with beta-blockers 1
• This distinguishes it from non-dihydropyridine calcium channel blockers 1

Special Population Warnings

Elderly Patients (If Applicable)

• Start at 2.5mg in elderly patients rather than 5mg due to 40-60% increased drug exposure from decreased hepatic clearance 5, 1
• Monitor specifically for orthostatic hypotension, falls, and syncope in the first 2-3 weeks 5
• Blood pressure should be checked both sitting and standing 5

Hepatic Impairment (If Applicable)

• Patients with liver disease require slower titration due to 56-hour half-life in hepatic impairment (versus 30-50 hours normally) 1
• Start at 2.5mg and increase very gradually if needed 1

Practical Patient Counseling Points

Timing and Adherence

• Take once daily at the same time each day—the long half-life provides 24-hour blood pressure control 7
• Full blood pressure effect takes 4 weeks to develop, so don't expect immediate results 1
• Side effects, if they occur, are typically mild and transient, resolving within the first few weeks 2, 4

When to Call

• Report ankle swelling if bothersome (most common reason to adjust therapy) 3
• Report any new or worsening chest pain immediately (especially if patient has coronary disease) 1
• Report severe headache, severe dizziness, or fainting (though uncommon) 3

Reassurance

• Amlodipine is one of the best-tolerated calcium channel blockers with significantly fewer vasodilatory side effects than other dihydropyridines like nifedipine or nitrendipine 4
• The gradual onset and long duration of action account for the excellent tolerability profile 4
• Overall tolerability is rated as excellent or good in 91% of patients 3