What is the recommended initial dose and monitoring plan for amlodipine in a 58‑year‑old woman with hypertension and a prior myocardial infarction?

Starting Amlodipine in a 58-Year-Old Woman with Hypertension and Prior Myocardial Infarction

Begin amlodipine at 5 mg once daily in the morning, and plan to add an ACE inhibitor or ARB within 2–4 weeks if blood pressure remains ≥140/90 mmHg, rather than relying on amlodipine monotherapy or dose escalation alone. 1

Initial Dosing Strategy

• Start amlodipine 5 mg once daily as the initial antihypertensive dose; this is the FDA-approved starting dose for adults and provides effective 24-hour blood pressure control with once-daily administration. 1, 2
• Small, fragile, or elderly patients may be started on 2.5 mg once daily, but a 58-year-old woman without specified frailty or hepatic insufficiency should receive the standard 5 mg dose. 1
• Amlodipine can be taken at any time of day that is most convenient for the patient to maximize adherence. 1

Blood Pressure Targets and Monitoring Timeline

• Target blood pressure is <130/80 mmHg for this patient with established cardiovascular disease (prior MI), with a minimum acceptable goal of <140/90 mmHg. 3
• Re-measure blood pressure 2–4 weeks after initiating amlodipine to assess response, measuring at trough (just before the next dose) to confirm 24-hour control. 3, 1
• Wait 7 to 14 days between titration steps under usual circumstances, though more rapid titration is appropriate if blood pressure remains severely elevated (≥160/100 mmHg) and the patient is assessed frequently. 1

Why Combination Therapy Should Be Planned Early

• In a patient with prior MI, amlodipine monotherapy is insufficient—she requires renin-angiotensin system blockade (ACE inhibitor or ARB) for secondary prevention of cardiovascular events. 4
• The 2013 ACCF/AHA STEMI guideline gives a Class I recommendation for ACE inhibitors in patients with anterior infarction, post-MI left ventricular systolic dysfunction (EF ≤0.40), or heart failure, and states they may be given routinely to all post-MI patients without contraindication. 4
• Adding an ACE inhibitor or ARB to amlodipine provides complementary mechanisms—vasodilation through calcium channel blockade plus renin-angiotensin system inhibition—and achieves superior blood pressure control compared to either agent alone. 5
• Combination therapy (amlodipine + ACE inhibitor/ARB) yields an additional systolic reduction of approximately 10–20 mmHg, far exceeding the ~1.6–3.3 mmHg gained by increasing amlodipine from 5 mg to 10 mg. 5

Dose Escalation vs. Adding a Second Agent

• If blood pressure remains ≥140/90 mmHg after 2–4 weeks on amlodipine 5 mg, add an ACE inhibitor (e.g., lisinopril 10 mg daily) or ARB (e.g., losartan 50 mg daily) rather than increasing amlodipine to 10 mg. 5
• The maximum amlodipine dose is 10 mg once daily, but dose escalation alone is less effective than combination therapy for achieving blood pressure goals. 1, 5
• Increasing amlodipine to 10 mg is reasonable only if there is documented intolerance or contraindication to both ACE inhibitors and ARBs, which is uncommon. 5

Specific ACE Inhibitor/ARB Dosing for Post-MI Patients

• Lisinopril: Start 2.5–5 mg daily, titrate to 10 mg daily or higher as tolerated. 4
• Captopril: Start 6.25–12.5 mg three times daily, titrate to 25–50 mg three times daily as tolerated. 4
• Ramipril: Start 2.5 mg twice daily, titrate to 5 mg twice daily as tolerated. 4
• Trandolapril: Test dose 0.5 mg, titrate up to 4 mg daily as tolerated. 4
• ARBs (if ACE inhibitor intolerant): Valsartan 20 mg twice daily, titrate to 160 mg twice daily as tolerated. 4

Monitoring After Adding ACE Inhibitor or ARB

• Check serum potassium and creatinine 2–4 weeks after starting an ACE inhibitor or ARB to detect hyperkalemia or acute kidney injury, especially important in post-MI patients who may have reduced renal perfusion. 5
• Monitor for ACE inhibitor-specific adverse effects: dry cough (5–10% of patients), hyperkalemia, and acute kidney injury. 5
• Monitor for ARB-specific adverse effects: hyperkalemia and acute kidney injury (cough is rare with ARBs). 5

Escalation to Triple Therapy if Needed

• If blood pressure remains ≥140/90 mmHg after optimizing amlodipine + ACE inhibitor/ARB, add a thiazide-like diuretic (chlorthalidone 12.5–25 mg daily preferred over hydrochlorothiazide 25 mg daily) as the third agent. 3, 5
• The triple combination of ACE inhibitor/ARB + calcium channel blocker + thiazide diuretic is guideline-recommended, targeting volume reduction, vasodilation, and renin-angiotensin system blockade. 3, 5
• Chlorthalidone is preferred over hydrochlorothiazide because of its longer duration of action (24–72 hours vs. 6–12 hours) and superior cardiovascular outcome data from the ALLHAT trial. 3

Special Considerations in Post-MI Patients

• Beta-blockers are also indicated for secondary prevention post-MI (Class I recommendation), but should not replace amlodipine or ACE inhibitor/ARB therapy. 4
• Oral beta-blockers should be given to all post-MI patients without contraindication: metoprolol tartrate 25–50 mg every 6–12 hours, titrate to 200 mg daily as tolerated; or carvedilol 6.25 mg twice daily, titrate to 25 mg twice daily as tolerated. 4
• Avoid beta-blockers initially if the patient has signs of heart failure, low output state, increased risk of cardiogenic shock, prolonged first-degree or high-grade AV block, or reactive airways disease. 4
• Statins are mandatory for all post-MI patients—initiate high-dose atorvastatin 80 mg daily for secondary prevention. 4

Contraindications and Cautions for Amlodipine

• Avoid amlodipine in patients with hypotension (systolic BP <90 mmHg or >30 mmHg below baseline). 4
• Amlodipine is safe in patients with asthma or COPD and does not provoke bronchoconstriction. 3
• Common side effects include peripheral edema (10–30% at 10 mg dose), headache, flushing, and constipation; adding an ACE inhibitor or ARB can lessen amlodipine-related peripheral edema. 5, 1

Lifestyle Modifications (Adjunctive to Pharmacotherapy)

• Sodium restriction to <2 g/day yields a 5–10 mmHg systolic reduction and enhances the efficacy of all antihypertensive classes, especially diuretics and ACE inhibitors. 3
• Weight loss (if BMI ≥25 kg/m²)—losing ~10 kg reduces blood pressure by approximately 6.0/4.6 mmHg. 3
• DASH dietary pattern (high in fruits, vegetables, whole grains, low-fat dairy; low in saturated fat) lowers blood pressure by roughly 11.4/5.5 mmHg. 3
• Regular aerobic exercise (≥30 minutes most days, ~150 minutes/week moderate intensity) reduces blood pressure by ~4/3 mmHg. 3
• Limit alcohol intake to ≤1 drink/day for women, as excess consumption interferes with blood pressure control. 3
• Tobacco cessation is mandatory—smoking independently drives cardiovascular disease and mortality, and quitting before middle age restores life expectancy to that of lifelong non-smokers. 5

Critical Pitfalls to Avoid

• Do not rely on amlodipine monotherapy in a post-MI patient—she requires ACE inhibitor or ARB for secondary prevention regardless of blood pressure control. 4
• Do not combine an ACE inhibitor with an ARB (dual RAS blockade), as this increases hyperkalemia and acute kidney injury without added cardiovascular benefit. 3, 5
• Do not add a beta-blocker as the second antihypertensive agent unless there are compelling indications (angina, post-MI, heart failure with reduced ejection fraction, atrial fibrillation requiring rate control); beta-blockers are less effective than ACE inhibitors or thiazide diuretics for stroke prevention in uncomplicated hypertension. 3
• Do not delay treatment intensification when blood pressure remains ≥140/90 mmHg; prompt action within 2–4 weeks is required to reduce cardiovascular risk. 3, 5
• Do not assume treatment failure without first confirming medication adherence and excluding white-coat hypertension with home blood pressure monitoring (≥135/85 mmHg) or 24-hour ambulatory monitoring (≥130/80 mmHg). 3, 5

Long-Term Goal

• Achieve target blood pressure <130/80 mmHg within 3 months of initiating or modifying therapy, with reassessment every 2–4 weeks until goal is reached. 3, 5