From the Research
For non-sustained ventricular tachycardia (NSVT), metoprolol succinate is generally preferred over metoprolol tartrate due to its extended-release formulation that provides more consistent beta-blockade throughout a 24-hour period with once-daily dosing. Metoprolol succinate typically starts at 25-50 mg once daily and can be titrated up to 200 mg daily as needed 1. The extended-release formulation helps maintain more stable blood levels, potentially reducing breakthrough arrhythmias and minimizing peak-related side effects like dizziness or hypotension. This consistent beta-blockade is particularly important for managing ventricular arrhythmias like NSVT, where fluctuations in sympathetic tone can trigger events. However, metoprolol tartrate can still be effective when dosed properly (typically 25-100 mg twice daily), and some patients may need to start with the immediate-release formulation to establish tolerance before switching to succinate. Both formulations work by blocking beta-1 adrenergic receptors, reducing heart rate, contractility, and conduction velocity, which helps suppress ventricular ectopy and prevent sustained arrhythmias. Some studies have shown that metoprolol succinate may not be effective in all patients, particularly those with high PVC burden, and may even have a proarrhythmic effect in some cases 1. However, the most recent and highest quality study available does not specifically address the comparison between metoprolol succinate and tartrate for NSVT, but the general consensus in the medical community is to prefer metoprolol succinate due to its pharmacokinetic properties. Key points to consider when choosing between metoprolol succinate and tartrate include:
- The need for consistent beta-blockade throughout the day
- The potential for breakthrough arrhythmias with metoprolol tartrate
- The importance of minimizing peak-related side effects
- The possibility of a proarrhythmic effect with metoprolol succinate in some patients. Overall, metoprolol succinate is the preferred choice for NSVT due to its extended-release formulation and consistent beta-blockade 2.