What is the equivalency between metoprolol tartrate and metoprolol succinate for a patient with hypertension or heart failure?

Metoprolol Tartrate to Succinate Equivalency

For dose conversion: 100 mg of metoprolol tartrate (given as 50 mg twice daily) is approximately equivalent to 100 mg of metoprolol succinate (given as 100 mg once daily), though this represents bioequivalence rather than therapeutic equivalence, and the formulations are NOT interchangeable for heart failure patients. 1

Critical Formulation Distinction

The most important consideration is NOT the dose conversion, but rather which clinical condition you are treating:

For Heart Failure with Reduced Ejection Fraction (HFrEF)

• Only metoprolol succinate is proven to reduce mortality (34% reduction) and should be used exclusively 2, 3
• Metoprolol tartrate showed inferior outcomes compared to carvedilol in the COMET trial and lacks mortality benefit in heart failure 2, 3
• Never substitute metoprolol tartrate for metoprolol succinate in heart failure patients—this is a critical clinical pitfall 3
• Target dose: 200 mg once daily of metoprolol succinate, starting at 12.5-25 mg once daily 2, 3

For Hypertension or Angina

• Both formulations are acceptable, with dose equivalency of approximately 1:1 2, 1
• Metoprolol tartrate: 25-100 mg twice daily (total 50-200 mg/day) 2
• Metoprolol succinate: 50-200 mg once daily 2, 4
• Metoprolol succinate is preferred due to once-daily dosing, better adherence, and more consistent 24-hour blood pressure control 4

Pharmacokinetic Basis for Conversion

• A 100-mg metoprolol controlled/extended-release tablet contains 95 mg of metoprolol succinate and is considered equivalent in beta-blocking activity to 100 mg metoprolol tartrate 1
• However, metoprolol succinate provides consistent plasma concentrations over 20 hours, while metoprolol tartrate produces marked peaks and troughs 3, 1
• This pharmacokinetic difference translates to different clinical outcomes, particularly in heart failure 3, 5

Practical Conversion Algorithm

When converting from tartrate to succinate:

1. First, identify the indication:

   • If heart failure → Must use succinate; start fresh with guideline-directed dosing (12.5-25 mg daily, titrate to 200 mg) 2, 3
   • If hypertension/angina → Can use 1:1 total daily dose conversion 2, 1

2. For hypertension/angina conversion:

   • Metoprolol tartrate 50 mg twice daily (100 mg/day) → Metoprolol succinate 100 mg once daily 2, 1
   • Metoprolol tartrate 100 mg twice daily (200 mg/day) → Metoprolol succinate 200 mg once daily 2, 4

3. Monitor during transition:

   • Blood pressure and heart rate 4
   • Symptoms of hypotension or bradycardia 2

Common Pitfalls to Avoid

• Never use metoprolol tartrate 50 mg twice daily as a substitute for metoprolol succinate in heart failure—this was neither the dose nor formulation that showed mortality reduction in trials 2
• Never abruptly discontinue either formulation, as this may precipitate angina, myocardial infarction, or arrhythmias 2
• Do not assume therapeutic equivalence based solely on dose equivalence—the sustained-release properties of succinate provide clinical advantages beyond simple bioequivalence 3, 5
• For patients with comorbid heart failure, always use metoprolol succinate regardless of the primary indication 4, 3