Psych Drugs Linked to MI Risk in Dementia

Older patients with dementia face a time-limited increased risk of heart attack if they are placed on antipsychotic medications, researchers reported.

In a retrospective cohort study, community-dwelling seniors placed on antipsychotic drugs had a significantly increased risk of heart attack in the first month after they began taking the medications, with a hazard ratio of 2.19 (95% CI 1.11 to 4.32) compared with dementia patients not taking antipsychotic medications, according to Yola Moride, PhD, of the Université de Montréal in Montreal, and colleagues.

But the risk gradually trailed off over the next year, Moride and colleagues reported online in Archives of Internal Medicine.

While antipsychotic medications are not indicated in dementia, they are commonly prescribed to help control some of the side effects, such as aggression and hallucinations, the researchers noted.

One clinical implication of the current study is that doctors should be cautious about using the medications, according to Sudeep Gill, MD, and Dallas Seitz, MD, both of Queen's University in Kingston, Ontario.

Action Points

Point out that these studies suggest that there is a modest and time-limited risk for acute myocardial infarction during the first 30 days after initiation of antipsychotic drugs.
Note that the study authors said the findings suggest a risk increase that is highest at the beginning of treatment and seems to decrease thereafter.

In an accompanying comment article, Gill and Seitz argued that physicians should "use other techniques when available, such as environmental and behavioral strategies, to keep these patients safe and engaged."

Although the underlying mechanisms remain unclear, several studies have found an increased risk of cardiovascular events and death when demented patients are treated with antipsychotics. Regulatory agencies have issued warnings about the issue.

But the effect of antipsychotic drugs on the risk of acute myocardial infarction (MI) hasn't been studied in depth, Moride and colleagues noted.

To help fill the gap, they turned to data from the public prescription drug and medical services programs in the Canadian province of Quebec, which cover more than 98% of the province's citizens who are 65 and older.

For this analysis, the researchers studied 37,138 people 66 and older who lived in the community and had become new users of cholinesterase inhibitors between Jan. 1, 2000, and Dec. 31, 2009, but were not immediately using antipsychotics.

Of those, Moride and colleagues reported, 10,969 (or 29.5%) started antipsychotic drugs during the study period.

For Cox proportional hazards modeling, they were matched with random sample of the members of the cohort who did not start the medications. Follow-up covered the year after starting antipsychotics.