Over-the-counter cough and cold medication use and risk of stroke.

Abstract

To the Editor: I read with great interest the study by Cantu et al1 in Stroke that evaluated the association between over-the-counter cough and cold medications containing sympathomimetics and stroke risk. Their study covers an important topic—risk factor assessment of acute stroke and, in particular, drug-induced stroke. The authors use data from a stroke registry including 2500 patients with a diagnosis of acute stroke in Tlalpan, Mexico. The study related 22 cases of stroke with over-the-counter cough and cold medication use, when such medications were taken within 24 hours prior to the stroke and other known causes of stroke were excluded by appropriate diagnostic tests. There are several issues that should be taken into account when assessing the association between over-the-counter cough and cold medication use and stroke risk described in the study by Cantu et al. This study is technically a case series in which outcome and exposure were assessed at the same time. To evaluate an apparent association between over-the-counter cough and cold medication and stroke, a comparison group is essential to determine if the risk of stroke is increased or decreased when using such medications. The study, however, does not provide information regarding over-the-counter cough and cold medication use in the remaining patients from the stroke registry and, more important, in the general population. The use of a case-crossover design2 would allow a comparison of short-term exposures and stroke risk in a series of cases only and might have been applicable to the data of Cantu et al. Because over-the-counter drugs are available without prescriptions, they tend to be widely used in the general population. It is thus not entirely surprising that in a series of cases some individuals without obvious other reasons for stroke are using such medications even shortly before to a stroke. …