From the Guidelines
Metoprolol is generally a safer choice than atenolol for managing anxiety in a patient who experiences wheezing with propranolol. Both metoprolol and atenolol are cardioselective beta-blockers, meaning they primarily block beta-1 receptors in the heart rather than beta-2 receptors in the lungs, making them less likely to cause bronchospasm compared to non-selective agents like propranolol 1. However, metoprolol is often preferred over atenolol because it has better penetration into the central nervous system, which may provide better anxiolytic effects, and it has a more favorable metabolic profile.
Key Considerations
- Metoprolol is typically started at 25-50 mg twice daily for anxiety symptoms, with dosage adjustments based on response and tolerability.
- Even though metoprolol is cardioselective, it's essential to monitor for respiratory symptoms, especially at higher doses where selectivity may be lost.
- Any beta-blocker should be used cautiously in patients with a history of reactive airway disease, and starting with a low dose while monitoring for wheezing or shortness of breath is advisable, as suggested by guidelines for managing patients with unstable angina/non ST-elevation myocardial infarction 1.
- Alternative anxiety treatments such as SSRIs or cognitive behavioral therapy might be considered if beta-blockers continue to cause respiratory issues.
Evidence Summary
The ACC/AHA UA/NSTEMI Guideline Revision 1 and the European Society of Cardiology guidelines on the management of stable angina pectoris 1 support the use of beta-1 selective agents like metoprolol for their effectiveness in reducing anginal symptoms and ischemia, with advantages concerning side-effects and precautions when compared with non-selective beta-blockers.
Clinical Decision
Given the patient's history of wheezing with propranolol, metoprolol is the preferred choice due to its cardioselectivity and lower risk of exacerbating respiratory symptoms, as well as its potential for better anxiolytic effects and a more favorable metabolic profile compared to atenolol 1.
From the Research
Comparison of Atenolol and Metoprolol for Anxiety
- Atenolol and metoprolol are both beta-blockers that can be used to manage anxiety, but their effectiveness and safety profiles differ 2, 3.
- Atenolol has been shown to be well-tolerated and effective in treating anxiety disorders, with 86% of patients reporting a positive effect and 90% denying adverse effects or finding them tolerable 2.
- Metoprolol, on the other hand, has been found to have a lower incidence of central nervous system effects compared to propranolol, but its effectiveness in treating anxiety disorders is not well-established 3, 4.
Safety Considerations
- Propranolol, a non-selective beta-blocker, can cause wheezing in some patients, making it a less suitable option for those with respiratory issues 5, 3.
- Atenolol and metoprolol are both cardioselective beta-blockers, which means they are less likely to cause wheezing and other respiratory problems compared to non-selective beta-blockers like propranolol 3, 4.
- However, metoprolol has been found to have a lower incidence of adverse effects on beta 2-adrenoceptor mediated bronchodilatation compared to atenolol, making it a potentially safer option for patients with asthma or other respiratory conditions 4.
Efficacy of Beta-Blockers for Anxiety
- The current evidence on the effectiveness of beta-blockers for anxiety disorders is limited and inconclusive, with some studies suggesting that they may not be effective in treating anxiety disorders like social phobia or panic disorder 5, 6.
- A systematic review and meta-analysis found no evidence for a beneficial effect of beta-blockers compared to placebo or benzodiazepines in patients with social phobia or panic disorder 6.
- Further studies are needed to determine the efficacy and safety of beta-blockers, including atenolol and metoprolol, for the treatment of anxiety disorders 2, 6.