Side effects of metoprolol
Pro Research Analysisby 
Searched over 200M research papers
Common Side Effects of Metoprolol
Metoprolol, a beta-blocker widely used for cardiovascular conditions, is associated with several common side effects. The most frequently reported include tiredness, dizziness, bradycardia (slow heart rate), hypotension (low blood pressure), and dyspnea (shortness of breath) Ca1983Bahar2018. These effects are generally mild but can be more pronounced in some patients, especially those with underlying health conditions or those taking higher doses.
Central Nervous System (CNS) Side Effects of Metoprolol
Sleep Disturbances, Nightmares, and Hallucinations
Metoprolol is known to cause central nervous system side effects, particularly due to its lipophilic nature, which allows it to cross the blood-brain barrier more easily. Patients have reported vivid and bizarre dreams, nightmares, sleep disturbances, hallucinations, confusion, and even psychosis Cove-Smith1985Koshy2024Shah2020+2 MORE. These effects are more common in elderly patients and those sensitive to CNS-active medications. Discontinuation of metoprolol often leads to improvement in these symptoms Cove-Smith1985Koshy2024Shah2020+1 MORE.
Psychiatric and Cognitive Effects
Some patients experience increased anxiety, problems with concentration and memory, decreased energy, and, in rare cases, delirium or psychosis Cove-Smith1985Shah2020A.H.Husain2019. There have also been reports of suspected suicide associated with metoprolol use, highlighting the need for careful monitoring of mood and mental health, especially in vulnerable populations .
Cardiovascular and Autonomic Side Effects
Metoprolol can cause bradycardia and hypotension, which are among the most commonly observed adverse effects Rafique2024Ca1983Bahar2018. Other cardiovascular-related side effects include lightheadedness, syncope (fainting), and, less commonly, orthostatic intolerance (difficulty standing due to blood pressure drops) Du2024Ca1983. These effects may be more pronounced in patients with certain genetic backgrounds or when metoprolol is combined with other medications that affect heart rate or blood pressure Ca1983Uddin2020.
Sexual Dysfunction
Some patients have reported sexual side effects, such as difficulty achieving satisfactory sexual intercourse, which may be related to the drug’s impact on the nervous system and blood flow .
Drug Interactions and Genetic Factors
Metoprolol is metabolized by the CYP2D6 enzyme. Drug interactions, especially with CYP2D6 inhibitors like paroxetine or fluoxetine, can increase metoprolol levels in the blood, leading to more pronounced side effects such as bradycardia and hypotension . However, in some populations, genetic variations in CYP2D6 do not appear to significantly affect the frequency of adverse effects .
Rare and Serious Adverse Reactions
Recent analyses have identified rare but serious adverse reactions, including trigemino-cardiac reflex (a sudden drop in heart rate and blood pressure), decorticate posture (abnormal body posture), and suspected suicide . These findings underscore the importance of ongoing monitoring and reporting of side effects.
Conclusion
Metoprolol is generally well-tolerated, but it can cause a range of side effects, most commonly tiredness, dizziness, bradycardia, and hypotension. Central nervous system effects such as sleep disturbances, vivid dreams, hallucinations, and psychiatric symptoms are also notable, especially in elderly patients. Rare but serious adverse reactions have been reported, emphasizing the need for careful patient monitoring, especially when combined with other medications or in those with predisposing factors. Regular review and patient education about potential side effects can help ensure safer use of metoprolol.
Sources and full results
Most relevant research papers on this topic