Background: Beta blockers are one of the medications most commonly prescribed for treating arrhythmias, hypertension, heart failure, and angina pectoris, and for helping prevent myocardial infarction (MI). Their use also has been shown to significantly reduce post-MI mortality. Despite this proven benefit, there are concerns about adverse effects. One such effect associated with lipophilic beta blockers is depression. However, recent studies assessing this adverse effect have been flawed. To address this, van Melle and colleagues evaluated the relationship between beta blocker use in patients with MI and the occurrence of depression.
The Study: Multiple centers were used to identify patients who had acute MI during the study period. Beta blocker use after acute MI was established during hospitalization. The generic name and medication dose were recorded, as well as whether the patient was being prescribed beta blockers for the first time or had already been using them. The beta blockers also were classified as lipophilic or hydrophilic, and dosages above or below the median were recorded.
The Beck Depression Inventory was used to assess depressive symptoms at baseline and at three, six, and 12 months into the study. Those with a positive score on the inventory were evaluated further with the Composite International Diagnostic Interview. Other variables included contraindications for beta blocker use, indicators and risk factors for cardiac disease, baseline depressive symptoms, and benzodiazepine use.
Results: Of 381 patients enrolled in the study, 254 received beta blockers at discharge, and 127 did not. Metoprolol (Lopressor) was the most common beta blocker prescribed, and only 7 percent of the beta blockers prescribed were hydrophilic. The most common reason for not using a beta blocker was bradyarrhythmia (28 percent), followed by chronic obstructive pulmonary disease (4 percent).
During the study, there were no significant differences in the presence of depressive symptoms or depressive disorders between the groups. Additionally, there were no differences between hydrophilic and lipophilic beta blockers and scores on the Beck Depression Inventory. However, patients who received high doses or long-term use of beta blockers did tend toward higher scores on the Beck Inventory at six and 12 months.
Conclusion: The use of beta blockers for patients recovering from MI is not associated with an increase in depressive symptoms or depressive disorders. The authors note that long-term use and higher doses may have an adverse effect on mood; however, further research is needed to explore this effect.