Grant: Operating Grant

Fainting affects about 50% of Canadians, is the cause of 1-2% of emergency room visits, and probably causes $250 million in health care spending each year. Frequent fainting causes a poor quality of life, and problems at work, at home, and while driving. The most common cause is reflex fainting. This occurs in people of all ages, and while many people only faint once or twice there are hundreds of thousand of Canadians who faint many times, and often more than once a year. Reflex fainting is due to abrupt drops in blood pressure and often drops in heart rate, and these reduce blood flow to the brain enough to make people lose consciousness. There is no known medical treatment for frequent fainting. One possible treatment would be to prevent the blood pressure drop by increasing the pressure in the veins and arteries. A drug called midodrine does this, by increasing blood flow to the heart and increasing blood pressure. It prevents lightheadedness and fainting in elderly people with damaged nerves around their blood vessels, and it might prevent reflex fainting. However there is no solid evidence of its effectiveness, and we will test whether midodrine prevents moderate to severe reflex fainting. We will study 128 patients who have fainted recently, have reflex fainting, and are at high risk of fainting again. They will enroll in a randomized clinical trial. Consenting patients will be assigned randomly to receive either midodrine or a dummy pill called a placebo, and we will follow them for 1 year. We then will compare the number of people who faint in those taking midodrine compared to placebo. We will also compare the frequency of fainting, quality of life, and health costs, in each arm of the study. This study will have centres in Canada, Europe and South America. It is the only study of its kind and it will be pivotal.