UK antidepressants may raise heart risk when paired with beta blockers, study warns

Thousands of patients in the United Kingdom may be at risk of life-threatening heart problems when antidepressants are taken with common beta-blockers, new research presented this week suggests. In a study of 65 adults who had both depression and high blood pressure, the combination of these drugs was linked to a higher likelihood of dangerously low blood pressure and bradycardia, or an abnormally slow heartbeat. The findings come as antidepressants remain widely prescribed in England, with about 8.6 million people receiving them last year, and roughly 60,000 beta-blocker prescriptions issued annually for heart conditions or to blunt physical anxiety symptoms such as palpitations and trembling.

The study focused on patients taking antidepressants such as selective serotonin reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors, including fluoxetine, sertraline, and venlafaxine, as well as duloxetine and bupropion. All participants were on a beta-blocker as well, and researchers found that the interaction was most pronounced with a subset of beta-blockers that are metabolized in the liver by the enzyme CYP2D6. These include metoprolol, carvedilol, and nebivolol. When CYP2D6 activity is inhibited by another medication, such as certain antidepressants, the beta-blocker can accumulate to unsafe levels in the body.

The researchers reported that people taking the combination experienced a 15-20% drop in blood pressure on average and a roughly 25% higher risk of bradycardia, a condition in which the heart beats too slowly. Severe hypotension can lead to dizziness, fainting, organ damage, and even shock, while bradycardia raises the risk of seizures, blackouts, and cardiac arrest. The study was unveiled at the American Heart Association's Hypertension Scientific Sessions 2025.

Lead author Dr. Inshal Jawed, a researcher at Dow Medical College in Karachi, said the magnitude of the interaction with nebivolol and other CYP2D6-metabolized beta blockers was striking, adding that clinicians should exercise caution when prescribing these beta blockers in combination with SSRIs or other CYP2D6 inhibitors. She stressed that dose adjustment and close monitoring are key, and that beta blockers less reliant on liver metabolism may be safer alternatives. Still, she cautioned that the analysis involved a relatively small patient group, and larger studies are needed to confirm the findings.

Not all beta blockers showed the same risk profile. The study did not observe a similar interaction among people taking atenolol or nadolol, which are processed differently by the body and less likely to interact with antidepressants. Dr. Jawed emphasized that clinicians should consider these pharmacokinetic differences when choosing a beta-blocker for patients who are also taking antidepressants. The researchers also highlighted the importance of awareness among prescribers about potential drug-drug interactions and the need for ongoing monitoring of blood pressure and heart rate after starting or adjusting therapy.

Warning signs of dangerously low blood pressure can include dizziness, blurred vision, nausea, fainting, and confusion. Symptoms of bradycardia may include chest pain, extreme fatigue, shortness of breath, and difficulty concentrating. For patients currently on antidepressants who are considering beta-blockers, or vice versa, health professionals say it is essential to review all medications for possible interactions and to adjust doses accordingly or choose alternatives where appropriate.

The findings arrive amid growing attention to the rising use of beta-blockers to manage anxiety. Propranolol, once primarily a heart medication, has become widely used off-label for situational anxiety, helping to blunt the physical signs of stress by blocking adrenaline and noradrenaline. While not considered addictive, experts stress that taking more than prescribed can be dangerous. Side effects can include tiredness, dizziness, and sleep disturbances, with more serious risks including heart failure, breathing difficulties, and severe allergic reactions. Public commentary has highlighted celebrity anecdotes about beta blockers helping with performance anxiety, but medical professionals caution that long-term benefit for chronic anxiety or panic disorders remains uncertain.

Dr. Amir Khan, a general practitioner, noted that many doctors prescribe beta-blockers for situational anxiety—such as before a public speaking event—rather than for long-term use. He stressed that when used acutely and judiciously, these medications can be helpful, but cautioned against routine, extended use without careful evaluation of risks and benefits. The new study reinforces the need for careful medication reconciliation and patient-specific risk assessment, especially for individuals concurrently taking antidepressants and beta-blockers with liver-metabolized pathways.

In the broader context, clinicians are urged to weigh the benefits of beta-blockers for anxiety against potential interactions with antidepressants and to consider alternative therapies or drug choices when appropriate. The study’s authors called for more extensive investigations to determine the generalizability of the results and to establish clear guidelines for managing these drug combinations. For now, patients should not discontinue prescribed medications without consulting their healthcare providers, and clinicians should monitor blood pressure and heart rate closely when initiating or adjusting therapy involving these drug classes.