What is the equivalent dose of metoprolol succinate (beta blocker) to metoprolol tartrate 50 mg twice daily?

Metoprolol Succinate Equivalent to Metoprolol Tartrate 50 mg

Metoprolol tartrate 50 mg twice daily (total daily dose 100 mg) is equivalent to metoprolol succinate 100 mg once daily. 1

Pharmacological Equivalence

• Metoprolol succinate is an extended-release formulation administered once daily, while metoprolol tartrate is an immediate-release formulation administered twice daily 1
• A 100 mg metoprolol succinate tablet contains 95 mg of metoprolol succinate and is considered to have equivalent activity to 100 mg metoprolol tartrate 2
• The extended-release formulation provides relatively constant plasma concentrations over approximately 20 hours, allowing for once-daily dosing 2

Conversion Guidelines

• When converting from metoprolol tartrate to metoprolol succinate, use the total daily dose of metoprolol tartrate to determine the appropriate once-daily dose of metoprolol succinate 1
• For metoprolol tartrate 50 mg twice daily (100 mg total daily dose), the equivalent metoprolol succinate dose is 100 mg once daily 1
• This equivalence is recognized by the American College of Cardiology and American Heart Association in their clinical practice guidelines 1

Clinical Considerations

• Metoprolol succinate's controlled-release mechanism works through individual pellets that act as diffusion cells, releasing the drug at a relatively constant rate 2
• Despite having lower peak plasma concentrations than metoprolol tartrate, metoprolol succinate maintains more consistent beta-blockade throughout the 24-hour period 3
• Clinical studies have demonstrated that the antihypertensive effect of metoprolol succinate 100-200 mg once daily is as effective as metoprolol tartrate 50-100 mg twice daily 4

Practical Application

• When prescribing, always clearly specify whether you're ordering metoprolol tartrate or metoprolol succinate to avoid confusion 1
• Be aware of different brand names (metoprolol tartrate as Lopressor vs. metoprolol succinate as Toprol-XL) which can cause prescribing errors 1
• For patients with hypertension, heart failure, or post-MI management requiring beta-blockade, either formulation can be used at the appropriate equivalent doses 5

Common Pitfalls to Avoid

• Don't confuse the dosing frequency - metoprolol tartrate requires twice-daily dosing while metoprolol succinate is administered once daily 1
• Although the systemic availability of metoprolol succinate is lower than metoprolol tartrate, the total clinical effect over 24 hours is similar due to the extended-release properties 3
• When transitioning between formulations, maintain the equivalent total daily dose to ensure consistent beta-blockade 1