In a patient with coronary artery disease and heart failure with reduced ejection fraction (45%) and resting blood pressure 120‑140 mm Hg who is taking metoprolol tartrate 25 mg orally twice daily, should I switch to metoprolol succinate (Toprol XL) 25 mg once daily?

Should You Switch from Metoprolol Tartrate to Metoprolol Succinate in HFrEF?

Yes, switch to metoprolol succinate (Toprol XL), but use 50 mg once daily, not 25 mg daily. Metoprolol succinate is the only metoprolol formulation proven to reduce mortality in heart failure with reduced ejection fraction, and your patient requires the evidence-based dose equivalent to achieve guideline-directed medical therapy. 1

Why Metoprolol Succinate is Superior

Metoprolol succinate (extended-release) is the specific beta-blocker formulation that demonstrated a 34% reduction in all-cause mortality in the landmark MERIT-HF trial, while metoprolol tartrate (immediate-release) has never been shown to reduce mortality in HFrEF. 2 The American College of Cardiology and European Society of Cardiology guidelines explicitly recommend only three evidence-based beta-blockers for HFrEF: carvedilol, metoprolol succinate, and bisoprolol—metoprolol tartrate is not among them. 1, 3

• The controlled-release formulation provides stable 24-hour beta-blockade, which is critical for neurohormonal suppression and mortality reduction in heart failure. 2
• Metoprolol succinate reduces sudden cardiac death and death from progressive heart failure when titrated to target doses. 2, 4
• The drug improves both systolic and diastolic left ventricular function, increasing ejection fraction and improving diastolic filling parameters. 5

Critical Dosing Error in Your Proposed Switch

Your proposed dose of 25 mg once daily is inadequate—the target dose of metoprolol succinate is 200 mg once daily, and your patient's current 50 mg total daily dose (25 mg twice daily tartrate) should convert to at least 50 mg once daily of succinate as a starting point. 1, 2 The MERIT-HF trial initiated therapy at 12.5-25 mg once daily and titrated upward every 2 weeks to reach the target 200 mg once daily dose. 2

• Starting at 25 mg once daily metoprolol succinate represents a 50% dose reduction from the current regimen (50 mg total daily tartrate dose), which would be a step backward in achieving guideline-directed therapy. 1
• The mortality benefit in HFrEF is achieved through forced-titration to target doses, not through low-dose therapy. 1, 3
• Accepting suboptimal beta-blocker dosing is one of the most common pitfalls in HFrEF management and reduces the survival benefit. 3

Recommended Conversion Strategy

Convert metoprolol tartrate 25 mg twice daily to metoprolol succinate 50 mg once daily initially, then up-titrate every 2 weeks toward the target dose of 200 mg once daily. 1, 2

Step-by-Step Titration Protocol

1. Week 0: Switch to metoprolol succinate 50 mg once daily (equivalent starting dose). 1
2. Week 2: Increase to metoprolol succinate 100 mg once daily if heart rate remains ≥70 bpm and blood pressure tolerates (SBP >80 mmHg). 3, 2
3. Week 4: Increase to metoprolol succinate 150 mg once daily. 2
4. Week 6: Increase to target dose of 200 mg once daily. 1, 2

• Monitor blood pressure, heart rate, and symptoms at each titration step. 6
• The patient's current blood pressure of 120-140 mmHg provides ample room for up-titration—do not withhold therapy for asymptomatic blood pressure readings above 80 mmHg. 1, 3

Blood Pressure Considerations

The patient's blood pressure of 120-140 mmHg is not a barrier to beta-blocker optimization—asymptomatic hypotension down to SBP 80 mmHg with adequate perfusion does not require dose reduction. 1, 3 Beta-blockers provide the highest relative mortality reduction (34%) among the four foundational HFrEF medication classes, making aggressive up-titration essential. 3

• Never discontinue or down-titrate beta-blockers for asymptomatic hypotension with adequate perfusion. 1, 3
• Adverse events occur in 75-85% of HFrEF patients regardless of treatment, with no substantial difference between guideline-directed therapy and placebo. 3

Complete HFrEF Medication Optimization

While switching to metoprolol succinate, ensure your patient is on all four foundational medication classes for HFrEF: an SGLT2 inhibitor, a mineralocorticoid receptor antagonist, a beta-blocker (metoprolol succinate), and an ARNI/ACE inhibitor/ARB. 1, 3 This quadruple therapy provides approximately 61% reduction in all-cause mortality and adds 5.3 life-years compared to no treatment. 3

• If not already prescribed, immediately add an SGLT2 inhibitor (dapagliflozin 10 mg daily or empagliflozin 10 mg daily) and a mineralocorticoid receptor antagonist (spironolactone 25 mg daily). 1, 3
• Consider switching from ACE inhibitor to sacubitril/valsartan if the patient has NYHA class II-IV symptoms, as ARNI provides superior mortality reduction. 1, 3

Common Pitfalls to Avoid

• Do not accept the 25 mg once daily dose as adequate therapy—this represents under-treatment and denies the patient proven mortality benefit. 1, 3
• Do not delay up-titration due to stable blood pressure—the patient's BP of 120-140 mmHg allows aggressive titration toward target doses. 1, 3
• Do not use metoprolol tartrate in HFrEF—only metoprolol succinate has proven mortality benefit. 1, 3
• Do not titrate multiple medications simultaneously—increase one drug at a time every 1-2 weeks to identify tolerance issues. 3, 6