Metoprolol Dosing Frequency
Metoprolol tartrate (immediate-release) is taken twice daily, while metoprolol succinate (extended-release) is taken once daily. 1, 2
Metoprolol Tartrate (Immediate-Release)
Standard oral dosing requires twice-daily administration:
- For hypertension: 25-100 mg twice daily 1, 2
- For atrial fibrillation rate control: 25-100 mg twice daily 1, 2
- For heart failure: Initial dose 25-50 mg twice daily, with maximum maintenance dose of 200 mg twice daily 2
- Post-myocardial infarction: 100 mg twice daily as maintenance dose after initial IV therapy 2, 3
The twice-daily dosing requirement stems from metoprolol tartrate's shorter half-life, necessitating more frequent administration to maintain therapeutic beta-blockade throughout the day. 2, 4
Metoprolol Succinate Extended-Release (Metoprolol XL/CR)
This formulation is designed for once-daily administration:
- For hypertension: 50-400 mg once daily 1, 2
- For atrial fibrillation rate control: 50-400 mg once daily 1, 2
- For heart failure with reduced ejection fraction: Initial dose 12.5-25 mg once daily, target dose 200 mg once daily 2, 5
The extended-release formulation provides sustained beta-blockade over 24 hours with more stable plasma levels and less peak-to-trough variation compared to immediate-release metoprolol. 6, 7 This once-daily dosing improves medication adherence while maintaining consistent therapeutic effect. 7, 8
Critical Formulation Distinction
Never confuse these formulations—they are not interchangeable on a milligram-per-milligram basis for all indications. 2, 5
For heart failure specifically, only metoprolol succinate (extended-release) has proven mortality benefit and should be dosed once daily at a target of 200 mg. 5 Metoprolol tartrate dosed twice daily has shown inferior outcomes in heart failure trials. 5
For hypertension and rate control, either formulation is acceptable, but the dosing frequency must match the formulation: tartrate twice daily, succinate once daily. 1, 2
Common Pitfall to Avoid
Do not prescribe metoprolol succinate twice daily—this deviates from evidence-based practice and the formulation's pharmacokinetic design. 5 The sustained-release preparation is specifically engineered for once-daily administration and was studied at this frequency in mortality-reduction trials. 5, 6