What is the next medication to consider for a patient with hypertension who is already on metoprolol (beta blocker)?

Next Medication for Elevated Blood Pressure on Metoprolol

Add an ACE inhibitor (such as lisinopril 2.5-10 mg daily) or ARB (such as losartan 50-100 mg daily) as the second antihypertensive agent to complement the beta-blocker mechanism. 1

Rationale for ACE Inhibitor/ARB Addition

• The guideline-recommended approach for hypertension management follows a stepwise algorithm: start with one first-line agent, then add a second agent from a complementary class (ACE inhibitor/ARB, calcium channel blocker, or thiazide diuretic). 1

• ACE inhibitors or ARBs provide complementary mechanisms of action to beta-blockers by targeting the renin-angiotensin system rather than heart rate and cardiac output, making them particularly beneficial for patients with chronic kidney disease, heart failure, or coronary artery disease. 1

• The combination of a beta-blocker with an ACE inhibitor/ARB has demonstrated superior blood pressure control compared to either agent alone, especially in patients with diabetes, chronic kidney disease, or heart failure. 1, 2

Alternative Second Agent: Calcium Channel Blocker

• If ACE inhibitors/ARBs are contraindicated or not tolerated, add a dihydropyridine calcium channel blocker (amlodipine 5-10 mg daily) as the second agent. 1, 3

• The combination of metoprolol with amlodipine provides complementary vasodilation alongside beta-blockade, with amlodipine's peripheral edema potentially attenuated by the ACE inhibitor if added subsequently. 1

When to Add a Third Agent

• If blood pressure remains uncontrolled after optimizing two agents at maximum tolerated doses, add a thiazide-like diuretic (chlorthalidone 12.5-25 mg daily or hydrochlorothiazide 25-50 mg daily) as the third agent to achieve guideline-recommended triple therapy. 1, 3

• The standard three-drug combination is: beta-blocker + ACE inhibitor/ARB + thiazide diuretic, or beta-blocker + calcium channel blocker + thiazide diuretic. 1

Target Blood Pressure and Monitoring

• Target blood pressure should be <140/90 mmHg for most patients, ideally <130/80 mmHg for higher-risk patients. 1, 3

• Reassess blood pressure within 2-4 weeks after adding the second agent, with the goal of achieving target blood pressure within 3 months of initiating or modifying therapy. 1, 3

Monitoring Parameters After Adding ACE Inhibitor/ARB

• Check serum potassium and creatinine 2-4 weeks after initiating ACE inhibitor/ARB therapy to detect potential hyperkalemia or acute kidney injury. 1

• Monitor for specific side effects including cough with ACE inhibitors (switch to ARB if occurs), hyperkalemia, and changes in renal function. 1

Critical Pitfalls to Avoid

• Do not add a second beta-blocker or increase metoprolol to very high doses as monotherapy—combination therapy with different drug classes is more effective than monotherapy dose escalation. 1

• Avoid combining ACE inhibitors with ARBs due to increased risk of adverse effects (hyperkalemia, hypotension, acute kidney injury) without additional blood pressure benefit. 1

• Do not delay treatment intensification if blood pressure remains significantly elevated (>160/100 mmHg), as this increases cardiovascular risk. 1

Fourth-Line Agent for Resistant Hypertension

• If blood pressure remains uncontrolled despite optimized triple therapy (beta-blocker + ACE inhibitor/ARB + thiazide diuretic), add spironolactone 25-50 mg daily as the preferred fourth-line agent for resistant hypertension. 1

• Monitor potassium closely when adding spironolactone to an ACE inhibitor/ARB, as hyperkalemia risk is significant with this combination. 1