Is Metoprolol (beta blocker) 50mg twice daily (bid) an excessive dose?

From the Guidelines

Metoprolol 50mg twice daily is not considered an excessive dose, as it falls within the recommended maintenance dose range of 200mg daily for metoprolol tartrate, as stated in the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1.

Key Considerations

• The dose of 50mg twice daily is within the therapeutic range for various conditions, including hypertension and heart failure.
• Side effects such as hypotension, bronchospasm, and bradycardia are potential risks, but their occurrence depends on individual patient factors and comorbidities 1.
• The guideline precautions for beta blockers, including metoprolol, advise against use in patients with AV block greater than first degree, decompensated systolic heart failure, hypotension, reactive airway disease, and severe renal dysfunction, among other conditions 1.

Monitoring and Adjustment

• Regular monitoring of heart rate, blood pressure, and symptoms is crucial to ensure the dose is appropriate for the patient's specific needs.
• If troublesome side effects occur, such as excessive fatigue, very low heart rate, or significant drops in blood pressure, the dose may need adjustment in consultation with a healthcare provider.
• Sudden discontinuation of metoprolol should be avoided due to the risk of rebound effects, including increased heart rate and blood pressure 1.

From the FDA Drug Label

DOSAGE & ADMINISTRATION ... In patients who tolerate the full intravenous dose (15 mg), initiate metoprolol tartrate tablets, 50 mg every 6 hours, 15 minutes after the last intravenous dose and continued for 48 hours. Thereafter, the maintenance dosage is 100 mg orally twice daily

• The maintenance dosage of metoprolol tartrate is 100 mg orally twice daily.
• The dose of 50 mg twice daily is less than the recommended maintenance dosage.
• Therefore, 50 mg twice daily is not considered an excessive dose, but rather lower than the standard maintenance dose for patients who have tolerated the initial doses 2.

From the Research

Dosage Information

• The typical dosage of metoprolol is not explicitly stated in the provided studies as being excessive or not, but the dosage of 50mg twice daily (bid) can be compared to the dosages used in the studies.
• In the study 3, it is mentioned that a twice daily dosage regimen is normally used, but the exact dosage is not specified.
• The study 4 mentions that treatment with metoprolol controlled-release/extended-release (CR/XL) was initiated at a low dosage of 12.5 to 25 mg once daily and gradually increased at 2-weekly intervals until the target dosage (200 mg once daily) or maximal tolerated dosage had been attained.
• The study 5 recommends initiating dose of metoprolol succinate at 12.5 mg and increasing gradually over weeks, with the target dose being the maximum tolerated for adequate bradycardia.
• The study 6 mentions that 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.
• The study 7 used dosages of metoprolol ranging from 150 to 300 mg/day, with significant reductions in angina frequency and increases in total work performed on a bicycle ergometer.

Comparison to Study Dosages

• The dosage of 50mg twice daily (bid) is lower than the higher dosages used in some of the studies, such as 200 mg once daily in study 4 and 300 mg/day in study 7.
• However, it is higher than the initiating dosages recommended in study 5 and used in study 4, which were 12.5 mg and 12.5 to 25 mg once daily, respectively.
• The dosage of 50mg twice daily (bid) is within the range of dosages that have been shown to be effective in reducing angina frequency and improving exercise tolerance in patients with angina pectoris, as seen in study 7.

Conclusion on Excessiveness

• Based on the provided studies, the dosage of 50mg twice daily (bid) does not appear to be excessively high, but rather within the range of dosages that have been used in clinical trials and shown to be effective.
• However, the optimal dosage of metoprolol may vary depending on the individual patient and their specific condition, and should be determined by a healthcare professional based on the patient's response to treatment and any potential side effects.