Can metoprolol tartrate (metoprolol) be dosed once a day?

Metoprolol Tartrate Dosing Frequency

Metoprolol tartrate should typically be dosed twice daily rather than once daily due to its relatively short half-life, unlike metoprolol succinate which is specifically formulated for once-daily dosing.

Pharmacokinetic Considerations

Metoprolol tartrate has a relatively short half-life that makes it unsuitable for once-daily dosing in most clinical scenarios:

• Metoprolol tartrate has a half-life of approximately 3-7 hours, which is insufficient to maintain therapeutic blood levels over 24 hours 1
• Guidelines from the American College of Cardiology/American Heart Association specifically list metoprolol tartrate with a recommended dosing frequency of twice daily 2
• In contrast, metoprolol succinate (extended-release) is specifically formulated for once-daily dosing through a controlled-release mechanism 3

Evidence from Guidelines

Multiple cardiovascular guidelines consistently recommend twice-daily dosing for metoprolol tartrate:

• The 2017 ACC/AHA hypertension guideline explicitly lists metoprolol tartrate with a daily frequency of "2" (twice daily) 2
• For acute management of supraventricular tachycardia, metoprolol tartrate is administered as 2.5-5.0 mg IV bolus over 2 minutes, which can be repeated in 10 minutes up to 3 doses 2
• When transitioning from IV to oral therapy, Praxis Medical Insights recommends starting with metoprolol 25mg orally every 6 hours for 48 hours before transitioning to maintenance dosing 4

Clinical Implications

Using metoprolol tartrate once daily may lead to:

• Inadequate beta-blockade during the latter part of the 24-hour period
• Fluctuating blood pressure control in hypertensive patients
• Inconsistent protection against angina symptoms
• Potential for rebound effects as drug levels decrease before the next dose

Alternative Options

If once-daily dosing is preferred for patient convenience or adherence:

1. Switch to metoprolol succinate: This extended-release formulation is specifically designed for once-daily dosing with equivalent beta-blocking effects 3

   • A 100mg metoprolol succinate tablet is equivalent to 100mg of metoprolol tartrate but provides steady drug release over approximately 20 hours

2. Consider other beta-blockers with longer half-lives:

   • Bisoprolol (once daily)
   • Atenolol (once daily)
   • Nadolol (once daily)
   • Carvedilol phosphate (once daily)

Special Considerations

While some early research suggested that once-daily metoprolol tartrate might be possible in certain hypertension cases 1, subsequent clinical practice and guidelines have consistently recommended twice-daily dosing for optimal therapeutic effect.

For patients where adherence is a concern with twice-daily dosing, switching to metoprolol succinate would be the preferred approach rather than attempting once-daily dosing with metoprolol tartrate.