What is the preferred formulation of metoprolol (beta blocker), metoprolol succinate or metoprolol tartrate, for a patient with hypertension (high blood pressure) or heart failure?

Metoprolol Succinate vs Metoprolol Tartrate: Clinical Selection Guide

For heart failure with reduced ejection fraction, metoprolol succinate (extended-release) is the only formulation proven to reduce mortality and should always be used; metoprolol tartrate has NOT demonstrated mortality benefit in heart failure and should be avoided. 1

Critical Distinction Between Formulations

Metoprolol succinate (CR/XL) is the controlled-release formulation that provides constant plasma concentrations over 24 hours with once-daily dosing, while metoprolol tartrate is the immediate-release formulation requiring twice-daily dosing with peak-and-trough plasma fluctuations. 2, 3, 4

For Heart Failure with Reduced Ejection Fraction (HFrEF)

Use metoprolol succinate exclusively - this is a Class I, Level A recommendation. 1

• Starting dose: 12.5-25 mg once daily 1
• Target dose: 200 mg once daily 1
• Titration schedule: Double dose every 1-2 weeks as tolerated 1

The MERIT-HF trial demonstrated that metoprolol succinate reduced all-cause mortality by 34%, sudden death by 49%, and death from progressive heart failure by 51% in patients with NYHA class II-IV heart failure. 5, 6 This mortality benefit was consistent across subgroups, including patients with hypertension and heart failure. 5

Critical caveat: Metoprolol tartrate should NOT be used for heart failure management, as it lacks mortality data and was inferior to carvedilol in the COMET trial. 1, 7 The European Society of Cardiology explicitly states that "metoprolol tartrate should not be used in preference to an evidence-based beta-blocker in HF." 1

For Hypertension

Either formulation is acceptable for blood pressure control alone, but metoprolol succinate offers practical advantages. 1, 4

• Metoprolol succinate: Once-daily dosing improves compliance, provides more consistent 24-hour blood pressure control, and causes fewer adverse effects due to avoidance of peak plasma concentrations. 2, 3, 4
• Metoprolol tartrate: Requires twice-daily dosing, which may reduce adherence. 4

However, for hypertension with compelling indications (post-MI, coronary disease, or heart failure), metoprolol succinate is strongly preferred as it addresses both conditions with proven mortality benefit. 1

For Stable Ischemic Heart Disease (SIHD) with Hypertension

Metoprolol succinate is preferred for once-daily convenience and proven cardiovascular event reduction. 1, 2

The 2017 ACC/AHA guidelines list both metoprolol tartrate and metoprolol succinate as acceptable GDMT beta-blockers for SIHD, but note that atenolol should be avoided as it is less effective than placebo in reducing cardiovascular events. 1

Practical Implementation Algorithm

Step 1: Identify the primary indication

• Heart failure with reduced EF → Metoprolol succinate only 1
• Hypertension alone → Metoprolol succinate preferred (once-daily dosing) 3, 4
• Post-MI or SIHD → Metoprolol succinate preferred 1, 2

Step 2: Initiate at appropriate dose

• Heart failure: Start 12.5-25 mg once daily of metoprolol succinate 1
• Hypertension: Start 25-100 mg once daily of metoprolol succinate 3, 4

Step 3: Titrate systematically

• For heart failure: Double dose every 1-2 weeks to target 200 mg daily 1
• Monitor for worsening heart failure, hypotension (SBP <90 mmHg), or bradycardia (HR <50 bpm) 1

Step 4: Manage adverse effects

• If worsening congestion: Increase diuretics first, then halve beta-blocker dose if needed 1
• If symptomatic hypotension: Reduce vasodilators before reducing beta-blocker 1
• If bradycardia <50 bpm with symptoms: Halve dose and review other rate-slowing drugs 1

Important Clinical Caveats

Never substitute metoprolol tartrate for metoprolol succinate in heart failure patients - they are not interchangeable despite similar beta-1 selectivity, as only the succinate formulation has mortality data. 1, 7

Dose equivalence: 100 mg of metoprolol succinate CR/XL contains 95 mg of metoprolol succinate salt and is considered equivalent to 100 mg of metoprolol tartrate in terms of beta-blockade, but the pharmacokinetic profiles differ substantially. 3

Consider carvedilol instead if the patient has refractory hypertension with heart failure, as carvedilol provides superior blood pressure reduction through combined α1, β1, and β2 blockade and demonstrated 17% greater mortality reduction compared to metoprolol tartrate in the COMET trial. 1, 7, 8

Avoid abrupt discontinuation of either formulation, as this risks rebound myocardial ischemia, infarction, and arrhythmias. 1