Antidopaminergic antiemetics (ADAs) that are widely used to relieve nausea and vomiting are associated with a heightened risk of ischaemic stroke, according to a study published by The BMJ.

The results of the study show that all three ADAs studied (domperidone, metopimazine, and metoclopramide) were associated with an increased risk, but the highest increase was found for metopimazine and metoclopramide.

The drugs are often taken by patients who suffer with migraines, have just come out of surgery, or are undergoing chemotherapy or radiotherapy.

Since ADAs work by blocking dopamine activity in the brain, the researchers say the potential action on blood flow to the brain could explain this higher risk.

The researchers analysed data from more than 2,500 stroke patients

The researchers from Inserm and Bordeaux University identified 2,612 patients from the the nationwide French reimbursement healthcare system database (SNDS) with a first ischaemic stroke between 2012 and 2016 and at least one reimbursement for domperidone, metopimazine or metoclopramide in the 70 days before their stroke.

They compared frequencies of these ADA reimbursements between a risk period (days -14 to -1 before stroke) and three matched reference periods (days -70 to -57, -56 to -43, and -42 to -29 before stroke).

Patients with stroke were then matched to a healthy control group of 21,859 randomly selected people who also received an ADA in the same time period.

New users of ADA could be at a 3-fold increased risk of stroke

Among patients with stroke, 1,250 received an ADA at least once in the risk period and 1,060 in the reference periods. Among the control group, 5,128 and 13,165 received an ADA at least once in the risk and reference periods, respectively.

After taking account of potentially influential factors, the researchers found that new users of ADA could be at a 3-fold increased risk of stroke shortly after treatment started. Men were particularly at risk, with a 3.59-fold increased risk. 

Higher risk found for drugs crossing the blood-brain barrier

The researchers note that the study is observational and cannot establish a cause. The study also had limitations including that data bases did not include information on prescribed daily dosage or duration of ADAs, as well as ischaemic stroke subtypes.

Even so, they say the results show that the risk of ischaemic stroke appears to be associated with ADA use, and suggest that "the higher risk found for drugs crossing the blood-brain barrier suggests a potential central effect, possibly through an action on cerebral blood flow."