Black Health
Beta blocker Heart failure Post-MI Angina Atrial fibrillation rate control

Metoprolol (Lopressor (tartrate), Toprol XL (succinate)) and Black patients

Brand names: Lopressor (tartrate), Toprol XL (succinate)

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What Metoprolol does

Metoprolol comes in two forms: metoprolol tartrate (immediate-release, twice-daily) and metoprolol succinate (extended-release, once-daily). Both are cardioselective beta blockers that slow the heart and reduce its workload. Metoprolol succinate is one of only three beta blockers with strong mortality-reduction data in heart failure with reduced ejection fraction.

What the evidence says for Black patients

Metoprolol is not first-line for uncomplicated hypertension in Black adults, for the same reasons as atenolol. But it is a first-line drug for several compelling indications, and here the Black-patient data are more nuanced:

  • Heart failure with reduced ejection fraction. Metoprolol succinate (Toprol XL) at target 200 mg daily reduces mortality in HFrEF (MERIT-HF, Lancet 1999;353:2001–7). The Black subgroup of MERIT-HF was small and the hazard ratio wider, but the effect direction was consistent. The BEST trial of bucindolol did show a race-treatment interaction (Eichhorn et al., NEJM 2001;344:1659–67), which prompted the carvedilol vs metoprolol debate; current consensus is that carvedilol and metoprolol succinate are both acceptable in Black HFrEF patients, with some preference for carvedilol based on COPERNICUS data.
  • Post-MI. Metoprolol tartrate is recommended after an acute myocardial infarction across all races.
  • Atrial-fibrillation rate control. Metoprolol works equivalently across racial groups for this indication.

The single most important prescribing point: do not substitute metoprolol tartrate for succinate in heart failure — only succinate has the mortality evidence, and generic pharmacy substitutions can make this error.

Common alternatives

For HFrEF in Black patients, carvedilol has the best-studied outcome data (COPERNICUS, NEJM 2001;344:1651–8). For post-MI, atenolol or metoprolol tartrate are both acceptable. Hydralazine plus isosorbide dinitrate (BiDil) is a race-specific additional therapy for Black HFrEF patients based on the A-HeFT trial (Taylor et al., NEJM 2004;351:2049–57, PMID 15533851).

Side effects

  • Fatigue
  • Bradycardia
  • Dizziness, lightheadedness
  • Cold extremities
  • Sexual dysfunction
  • Masked hypoglycemia in diabetes
  • Bronchospasm in severe asthma (metoprolol is cardioselective but not bronchoselective at high doses)

Factors that affect adherence

The tartrate-vs-succinate confusion causes recurrent problems at pharmacies and in transitions of care. Patients should memorize which version they take and refuse a substitution without clinician approval. Generic succinate is inexpensive but sometimes has supply interruptions.

Questions to ask your doctor

Bring this list to your next appointment.

  • Am I on metoprolol tartrate or succinate? Is that the right one for my condition?
  • If I have heart failure, would carvedilol be a better choice?
  • What's my target heart rate on this drug?
  • What do I do if I miss a dose?

References

  1. MERIT-HF Study Group. Effect of metoprolol CR/XL in chronic heart failure. Lancet. 1999;353:2001–2007.
  2. Packer M, Coats AJ, Fowler MB, et al. Effect of carvedilol on survival in severe chronic heart failure (COPERNICUS). NEJM. 2001;344:1651–1658.
  3. Eichhorn EJ, Domanski MJ, Krause-Steinrauf H, et al. A trial of the beta-blocker bucindolol in patients with advanced chronic heart failure (BEST). NEJM. 2001;344:1659–1667.
  4. Heidenreich PA, Bozkurt B, Aguilar D, et al. 2022 AHA/ACC/HFSA Heart Failure Guideline. Circulation. 2022;145:e895–e1032.
  5. U.S. Food and Drug Administration. Toprol-XL (metoprolol succinate) label. https://www.accessdata.fda.gov/drugsatfda_docs/label/2008/019962s032lbl.pdf

Medical disclaimer

This page is patient education, not prescribing guidance. It summarizes the published evidence about how this medication has been studied in Black patients — it is not a substitute for the judgment of your personal clinician. Never start, stop, or change a prescription based on something you read here. If you have questions about your medication, call your prescriber or pharmacist. For emergencies, call 911.

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