What are the recommended first‑, second‑, and third‑line antihypertensive medications for an adult with uncomplicated primary hypertension, explained in simple terms?

First-, Second-, and Third-Line Antihypertensive Medications for Uncomplicated Primary Hypertension

First-Line Medications

For most adults with uncomplicated primary hypertension, start with a thiazide-like diuretic (chlorthalidone 12.5–25 mg daily), an ACE inhibitor, an ARB, or a long-acting calcium channel blocker. 1, 2

Specific First-Line Drug Names and Doses

Thiazide/Thiazide-Like Diuretics (Preferred):

• Chlorthalidone 12.5–25 mg once daily – strongest cardiovascular outcome evidence, superior for preventing heart failure and stroke 1, 2, 3
• Hydrochlorothiazide 25–50 mg once daily (less preferred than chlorthalidone) 1, 3
• Indapamide 1.25–2.5 mg once daily 1, 4

ACE Inhibitors:

• Lisinopril 10–40 mg once daily 1, 3
• Enalapril 5–40 mg once or twice daily 1, 5
• Ramipril 2.5–20 mg once daily 1, 3

Angiotensin Receptor Blockers (ARBs):

• Losartan 50–100 mg once daily 1, 5
• Valsartan 80–320 mg once daily 1
• Olmesartan 20–40 mg once daily 1

Long-Acting Calcium Channel Blockers:

• Amlodipine 5–10 mg once daily 1, 2, 4
• Extended-release nifedipine 30–90 mg once daily 1, 4

When to Use Monotherapy vs. Combination

Stage 1 hypertension (130–139/80–89 mmHg): Start with a single agent, titrate upward, then add a second drug from a different class if target not reached after 4 weeks 1, 2, 5

Stage 2 hypertension (≥140/90 mmHg or >20/10 mmHg above goal): Begin immediately with two-drug combination therapy, preferably as a single-pill formulation 1, 2, 5

Population-Specific First-Line Choices

Black patients without heart failure or CKD: Thiazide diuretic (chlorthalidone) or calcium channel blocker (amlodipine) – ACE inhibitors and ARBs are 30–36% less effective for stroke prevention in this population 1, 2, 5

Patients with diabetes: ACE inhibitor or ARB as initial therapy to protect kidney function 1, 4, 5

Patients with chronic kidney disease (stage 3+ or albuminuria ≥300 mg/day): ACE inhibitor or ARB 1, 4, 5

Second-Line Medications (Add-On Therapy)

When blood pressure remains ≥130/80 mmHg after 4 weeks on a single first-line agent at optimal dose, add a second drug from a different first-line class rather than maximizing the dose of the first drug. 1, 2, 5

Preferred Two-Drug Combinations

Most effective second-line combinations:

• Thiazide diuretic + ACE inhibitor or ARB 1, 5
• Calcium channel blocker + ACE inhibitor or ARB 1, 5

For Black patients:

• Thiazide diuretic + calcium channel blocker 1, 4

Beta-Blockers (Conditional Second-Line)

Beta-blockers should NOT be used as first-line therapy in uncomplicated hypertension, especially in patients >60 years, because they are approximately 36% less effective than calcium channel blockers and 30% less effective than thiazides for stroke prevention. 1, 2, 4, 5

Use beta-blockers as second-line only when there is a compelling indication:

• Post-myocardial infarction (continue ≥3 years) 1, 5
• Active angina 1, 5
• Heart failure with reduced ejection fraction 1, 5

Specific beta-blocker names and doses:

• Metoprolol succinate 50–200 mg once daily 1
• Carvedilol 12.5–50 mg twice daily 1
• Bisoprolol 2.5–10 mg once daily 1

Third-Line Medications (Triple Therapy)

If blood pressure remains ≥130/80 mmHg on two first-line agents at optimal doses, escalate to triple therapy: ACE inhibitor or ARB + calcium channel blocker + thiazide-like diuretic, preferably as a single-pill combination. 1, 4, 5

Fourth-Line for Resistant Hypertension

When blood pressure remains uncontrolled on three-drug therapy (including a diuretic), add:

Mineralocorticoid Receptor Antagonist (Preferred Fourth Agent):

• Spironolactone 25–50 mg once daily – most effective fourth-line agent for resistant hypertension 1, 4, 5
• Eplerenone 50–100 mg once or twice daily (less gynecomastia than spironolactone) 1

Alternative Fourth-Line Agents (if spironolactone contraindicated):

• Doxazosin 1–16 mg once daily (alpha-blocker) 1
• Hydralazine 100–200 mg twice daily (direct vasodilator) 1
• Clonidine 0.1–0.8 mg twice daily (central alpha-agonist) 1

Critical Monitoring for Spironolactone

Before starting spironolactone, verify serum potassium <5.0 mmol/L and eGFR >30 mL/min/1.73 m². 1, 4

Recheck potassium and creatinine within 1–2 weeks of initiation, after each dose increase, and every 3–6 months thereafter. 1, 4, 5

Medications to Avoid as First-Line

Alpha-blockers (doxazosin): Not first-line – 80% higher heart failure rate compared to chlorthalidone in ALLHAT trial 1, 2, 5

Beta-blockers: Not first-line in uncomplicated hypertension – inferior stroke prevention 1, 2, 4, 5

Dual RAS blockade: Never combine ACE inhibitor + ARB (or add aliskiren) – increases hyperkalemia and acute kidney injury without cardiovascular benefit 1, 4, 5

Blood Pressure Targets

Target <130/80 mmHg for all adults with hypertension, including those with diabetes, chronic kidney disease, or cardiovascular disease. 1, 2, 5

In high-risk patients, avoid lowering diastolic pressure below 60–70 mmHg – excessive reduction may increase adverse cardiovascular events. 1, 5

Follow-Up Schedule

Monthly visits after initiating or adjusting therapy until target blood pressure is achieved. 1, 2, 5

Every 3–5 months once blood pressure is controlled. 1, 2, 5

Space dose adjustments at least 4 weeks apart to allow full blood pressure response. 5