From the Guidelines
Metoprolol succinate is the preferred formulation for patients with heart failure due to its extended-release mechanism and once-daily dosing, which provides consistent blood levels and better adherence compared to metoprolol tartrate. The difference between metoprolol succinate and metoprolol tartrate lies in their formulation and dosing schedules. Metoprolol succinate is an extended-release formulation, typically available in doses of 25,50,100, and 200 mg, taken once daily, whereas metoprolol tartrate is an immediate-release formulation, commonly available in 25,50, and 100 mg tablets, requiring dosing two to three times daily.
Key Differences
- Metoprolol succinate provides consistent blood levels over 24 hours through its controlled-release system, whereas metoprolol tartrate has a more fluctuating blood level due to its immediate-release mechanism.
- The succinate formulation often provides better adherence due to less frequent dosing and may result in more consistent blood pressure control with fewer peak-related side effects.
- Both formulations contain the same active ingredient that blocks beta-1 adrenergic receptors, primarily affecting the heart by reducing heart rate and contractility.
Clinical Evidence
Studies such as the MERIT-HF trial 1 have demonstrated the efficacy of metoprolol succinate in reducing mortality in patients with heart failure. The 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults also recommends metoprolol succinate as a preferred agent for patients with heart failure 1.
Dosing Considerations
When converting between formulations, the total daily dose remains approximately the same, but the administration schedule changes. For example, metoprolol tartrate 50 mg twice daily would roughly equate to metoprolol succinate 100 mg once daily. The choice between formulations should consider patient preference, adherence challenges, and the specific condition being treated.
Recommendation
In patients with heart failure, metoprolol succinate is the preferred formulation due to its extended-release mechanism and once-daily dosing, which provides consistent blood levels and better adherence. This recommendation is based on the most recent and highest quality evidence available, including the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline 1 and the MERIT-HF trial 1.
From the Research
Formulation Differences
- Metoprolol succinate is a controlled-release/extended-release formulation designed to provide relatively constant metoprolol plasma concentrations and beta(1)-blockade while retaining the convenience of once daily administration 2.
- A 100-mg metoprolol controlled/extended-release tablet contains 95 mg of metoprolol succinate and is considered to have equivalent activity of 100 mg metoprolol tartrate 2.
- Metoprolol tartrate is an immediate-release formulation, which may lead to more fluctuation in metoprolol plasma concentrations compared to the extended-release formulation of metoprolol succinate 3.
Dosing Considerations
- Metoprolol succinate is administered once daily, providing consistent beta(1)-blockade over the 24-hour dosing interval 3.
- The dosing of metoprolol tartrate may need to be more frequent, typically twice daily, due to its immediate-release formulation.
- Studies have shown that metoprolol succinate and metoprolol tartrate have similar effects on mortality amongst patients with chronic heart failure, suggesting that the choice between the two formulations may depend on individual patient needs and preferences 4, 5, 6.
Key Points
- Metoprolol succinate and metoprolol tartrate are two different formulations of the same medication, with distinct pharmacokinetic and pharmacodynamic properties.
- The choice between metoprolol succinate and metoprolol tartrate should be based on individual patient characteristics, such as the need for once daily dosing and the presence of certain comorbidities.
- Further research is needed to fully understand the differences between metoprolol succinate and metoprolol tartrate in various patient populations.