Should a patient with paroxysmal atrial fibrillation (a fib) take metoprolol (Lopressor) in the morning if they have hypotension?

From the Guidelines

It is not recommended to take metoprolol in the morning if your blood pressure is 90s/50s, even if you have paroxysmal atrial fibrillation and are asymptomatic, as it can further lower your blood pressure to potentially dangerous levels. According to the acc/aha/esc 2006 guidelines for the management of patients with atrial fibrillation 1, beta blockers like metoprolol are recommended to control the heart rate in patients with persistent or permanent AF, but caution is advised in patients with hypotension. Key points to consider include:

• Measurement of heart rate at rest and control of the rate using pharmacological agents, such as beta blockers or nondihydropyridine calcium channel antagonists, are recommended for patients with persistent or permanent AF 1.
• Intravenous administration of beta blockers, such as metoprolol, is recommended to slow the ventricular response to AF in the acute setting, but caution is advised in patients with hypotension or heart failure 1.
• If you have a standing prescription for metoprolol to manage your paroxysmal atrial fibrillation, you should contact your healthcare provider for guidance before skipping a dose, as they may recommend temporarily holding the medication, reducing the dose, or switching to a different medication that has less effect on blood pressure. Some important considerations when taking metoprolol for paroxysmal atrial fibrillation include:
• Monitoring your blood pressure regularly to ensure it remains within a safe range
• Keeping a log of your blood pressure readings to share with your healthcare provider
• Adjusting your medication regimen as needed to balance the control of your arrhythmia with the maintenance of adequate blood pressure for organ perfusion.

From the FDA Drug Label

WARNINGS ... Bradycardia Bradycardia, including sinus pause, heart block, and cardiac arrest have occurred with the use of metoprolol. Patients with first-degree atrioventricular block, sinus node dysfunction, or conduction disorders may be at increased risk. Monitor heart rate and rhythm in patients receiving metoprolol. If severe bradycardia develops, reduce or stop metoprolol

• Bradycardia risk: The patient has paroxysmal a fib and a low blood pressure (90s/50s), which may increase the risk of bradycardia when taking metoprolol.
• Monitoring required: The drug label recommends monitoring heart rate and rhythm in patients receiving metoprolol, especially in those with conduction disorders. Given the patient's low blood pressure and asymptomatic status, it is recommended to exercise caution when administering metoprolol in the morning. The patient's heart rate and rhythm should be closely monitored, and the dose of metoprolol may need to be adjusted or stopped if severe bradycardia develops 2.

From the Research

Considerations for Taking Metoprolol in the Morning

• The patient's blood pressure is 90s/50s, which is considered low, but they are asymptomatic 3.
• Metoprolol is a beta-blocker that can lower blood pressure, so taking it in the morning may further decrease blood pressure 4, 5, 6, 7.
• However, the patient has paroxysmal atrial fibrillation, and metoprolol is often used to control heart rate in this condition 4, 5, 6, 7.
• Studies have compared the effectiveness of metoprolol and diltiazem for rate control of atrial fibrillation, with some showing similar efficacy and safety profiles 4, 5, 6, 7.
• One study found that intravenous diltiazem had higher efficacy and shorter average onset time compared to intravenous metoprolol, but with no significant difference in adverse events 6.
• Another study found that IV diltiazem was more effective than IV metoprolol for heart rate control in randomized trials, but not in observational studies 7.

Potential Risks and Benefits

• Taking metoprolol in the morning may help control the patient's heart rate, but it may also further decrease their already low blood pressure 3, 4, 5, 6, 7.
• The patient's asymptomatic status suggests that their low blood pressure may not be causing immediate harm, but it is still important to monitor their condition closely 3.
• The decision to take metoprolol in the morning should be made in consultation with a healthcare professional, taking into account the patient's individual needs and medical history 3, 4, 5, 6, 7.