Which is better for supraventricular tachycardia (SVT) and hypertension (HTN), metoprolol (beta-blocker) tartrate or metoprolol (beta-blocker) succinate?

Metoprolol Succinate vs. Tartrate for SVT and Hypertension

Metoprolol succinate (extended-release) is superior to metoprolol tartrate for managing both SVT and hypertension due to its once-daily dosing, more consistent plasma concentrations, and better 24-hour coverage. 1

Pharmacological Differences

• Metoprolol succinate provides relatively constant plasma concentrations over approximately 20 hours, avoiding the peaks and troughs associated with metoprolol tartrate 1
• Metoprolol succinate (50 mg QD) has a maximum daily maintenance dose of 400 mg QD, while metoprolol tartrate (25 mg BID) has a maximum daily maintenance dose of 200 mg BID 2
• Both formulations are beta-1 selective (cardioselective) adrenergic receptor blockers that reduce heart rate, cardiac output, and blood pressure 3

Efficacy for SVT Management

• Both metoprolol formulations are effective for SVT management by slowing AV nodal conduction and decreasing heart rate 4
• Metoprolol succinate provides more consistent beta-blockade throughout a 24-hour period, which is advantageous for preventing SVT recurrences 5
• Intravenous metoprolol has been shown to be effective in reducing ventricular rate in 81% of patients with supraventricular tachyarrhythmias, including 82% of patients with atrial fibrillation 6
• For acute SVT treatment, intravenous beta blockers (including metoprolol) are reasonable for hemodynamically stable patients, with a Class IIa recommendation (Level of Evidence: B-R) 2

Efficacy for Hypertension Management

• Metoprolol succinate was designed to overcome drug delivery problems of matrix-based sustained release forms by releasing the drug at a relatively constant rate over 24 hours 5
• The extended-release formulation (succinate) maintains clinically effective plasma concentrations within a narrow therapeutic range over the entire 24-hour dosing interval 5
• Metoprolol succinate may be associated with fewer side effects related to the central nervous system compared to other beta-blockers like atenolol or long-acting propranolol 5

Clinical Considerations

• For patients with both SVT and hypertension, metoprolol succinate's once-daily dosing may improve medication adherence compared to twice-daily metoprolol tartrate 1, 5
• In one comparative trial, carvedilol showed significantly reduced mortality compared to immediate-release metoprolol tartrate in heart failure patients, suggesting potential differences in clinical outcomes between beta-blocker formulations 2
• Both formulations share the same precautions: avoid in patients with AV block greater than first degree, SA node dysfunction, decompensated systolic heart failure, hypotension, and reactive airway disease 2

Dosing Recommendations

• For SVT management: Start metoprolol succinate at 50 mg QD with a maximum dose of 400 mg QD, or metoprolol tartrate at 25 mg BID with a maximum dose of 200 mg BID 2
• For hypertension management: Similar starting doses apply, with titration based on blood pressure response 1
• Monitor for common adverse effects including hypotension, bronchospasm, and bradycardia with either formulation 2

Potential Pitfalls

• Avoid abrupt discontinuation of either formulation as this may exacerbate angina and myocardial infarction 3
• Be cautious when switching between formulations; 100 mg of metoprolol tartrate is considered equivalent to 95 mg of metoprolol succinate 1
• Monitor for excessive bradycardia or hypotension, particularly when initiating therapy or increasing doses 7
• Neither formulation should be used in patients with pre-excited atrial fibrillation/flutter as they may increase ventricular response 4