Findings in a new Korean study suggest that taking medications containing caffeine may be tied to a doubled or even tripled risk of having a stroke.
These results seem to contradict recent evidence of caffeine’s protective effect, Reuters Health reports, but the findings may actually be in line with that research: people who drank the least coffee were most at risk when taking caffeinated drugs. The products studied were over-the-counter pain relievers, cold medicines and alertness aids containing small amounts of caffeine. “Caffeine is a vasoconstrictor, causing blood vessels to tighten and increasing the pressure of the blood flow,” Nam-Kyong Choi of Seoul National University College of Medicine, who co-led the study, told Reuters Health in an email.
The researchers studied three groups of adults: 940 patients who had suffered a hemorrhagic stroke, where a blood vessel in the brain bursts and bleeds heavily. They compared the stroke patients to similar patients who had been hospitalized but had not suffered a stroke and to a third group who had neither suffered a stroke nor been hospitalized. All participants were interviewed about the medications they had taken in the preceding two weeks. Those who had taken medications containing caffeine were about two and a half times more likely to suffer a stroke: 5 percent of the stroke group had taken a caffeine-containing medication versus 2.3 percent of the no-stroke groups. The findings were published in the journal Stroke.
When the researchers factored in coffee consumption, they learned that the participants who took caffeine-containing medications but didn’t drink coffee daily were closer to three times more likely to have strokes than people not taking the medications, according to Reuters Health. But adults who drank plenty of coffee daily did not seem to be at any greater risk. “Even though caffeine-containing medicines appear to increase the risk of hemorrhagic stroke, it doesn’t appear to be the ‘caffeine’ dose,” said Dr. Daniel Woo, associate professor of Neurology at the University of Cincinnati in Ohio, who was not involved in the study.
Woo said there are two important reasons why the new findings differ from the norm. Since this study could include only patients who were able to answer the researchers’ questions, the group did not represent stroke patients as a whole. Another consideration is the ingredients in the medicines. In Korea, cold medicines still contain phenylpropanolamine, or ephedrine, which raises blood pressure, and might have caused the strokes. Phenylpropanolamine was removed from medicines in the U.S. about 10 years ago when it was linked to increased risk of stroke.