Can metoprolol make you tired
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Can Metoprolol Make You Tired?
Introduction to Metoprolol and Fatigue
Metoprolol, a beta-blocker commonly prescribed for conditions such as hypertension and angina, has been studied extensively for its effects on exercise tolerance and subjective fatigue. This article synthesizes findings from multiple research studies to determine whether metoprolol can cause tiredness.
Exercise Tolerance and Subjective Fatigue
Impact on Exercise Performance
Several studies have investigated the effects of metoprolol on exercise performance. In a study comparing metoprolol and atenolol, it was found that both medications significantly reduced exercise heart rate and prolonged the time to complete exercise, which was associated with increased subjective fatigue . Another study comparing metoprolol with propranolol found that both drugs attenuated the systolic blood pressure response to exercise, but did not affect maximum oxygen consumption or the anaerobic threshold, suggesting that fatigue during exercise was not due to limited blood flow to the extremities .
Subjective Well-being and Fatigue
Research has also focused on the subjective well-being of individuals taking metoprolol. In a study involving elderly subjects, metoprolol in a controlled-release (CR) formulation did not show significant differences in subjective well-being compared to placebo, although atenolol caused a deterioration in vitality at peak plasma concentrations . Another study confirmed that metoprolol CR resulted in less fatigue during exercise compared to atenolol .
Pharmacokinetics and Fatigue
Plasma Concentration and Fatigue
The pharmacokinetic properties of metoprolol, particularly in its controlled-release form, contribute to its effects on fatigue. Metoprolol CR provides a more even plasma concentration-time profile over the dosage interval compared to atenolol, which peaks at 2-4 hours post-dose. This even profile may help mitigate the peaks and troughs that could contribute to feelings of fatigue 24.
Metabolism and Fatigue
The metabolism of metoprolol also plays a role in its side effects. A study found that poor metabolizers of debrisoquine experienced higher fatigue scores and longer exercise times compared to extensive metabolizers when taking metoprolol . This suggests that individual differences in drug metabolism can influence the degree of fatigue experienced.
Common Side Effects
General Side Effects
Metoprolol is generally well-tolerated, but common side effects include temporary fatigue, dizziness, and headache . In a study comparing diltiazem and metoprolol as add-on therapies for hypertension, tiredness was reported in 15.8% of patients on metoprolol . This indicates that while fatigue is a recognized side effect, it is not universally experienced by all patients.
Conclusion
In summary, metoprolol can cause tiredness, particularly in certain individuals and under specific conditions. The extent of fatigue may depend on factors such as the formulation of the drug, individual metabolism, and the presence of other medications. While metoprolol CR formulations appear to mitigate some of the fatigue associated with peak plasma concentrations, subjective fatigue remains a notable side effect for some users. Patients experiencing significant tiredness should consult their healthcare provider to discuss potential adjustments to their treatment regimen.
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