Results of recent studies indicate that Mirapex, a drug used to treat Parkinson’s disease and restless leg syndrome, may carry a risk of heart failure. The U.S. Food and Drug Administration (FDA) has not positively identified the risk and is working with the drug’s manufacturer, Boehringer Ingelheim, to conduct a further review.
Mirapex (pramipexole) was the subject of randomized clinical drug trials and after examining the data, the FDA found 12 cases of heart failure (among 4,157 patients) among those treated with Mirapex when compared to those patients taking a placebo (4 cases among 2,820). Those numbers are not considered statistically significant. Epidemiological studies also suggest a link, however the data is not conclusive.
But when two studies from Europe were compared the data was considered statistically significant. In those cases, the risk of heart failure rate among patients ages 40-89, treated with anti-Parkinson’s disease drugs, increased the risk of heart failure when compared to a placebo by almost 60 percent. The relative risk for Mirapex was 1.86 and 2.07 when the data was combined with another dopamine agonist, cabergoline.
Mirapex also did not do well when compared to the dopamine drug, levodopa, increasing the risk for a heart attack in the first three months of treatment among patients age 80 and older. After three months, the increased risk for heart failure was not considered significant.
Mirapex is a member of a class of drugs approved in July 1997 called dopamine agonists. It is prescribed off-label to treat sexual dysfunction and cluster headaches and is being investigated as a treatment for depression and fibromyalgia. It has some of the same effects as the naturally occurring dopamine in the brain.
Patients are encouraged to contact their doctor if they experience shortness of breath with exercise when taking Mirapex as well as swelling of the lower extremities, fatigue, weakness, a rapid or irregular heartbeat, wheezing, or chest pain. They are also advised to continue taking the drug unless otherwise directed by their healthcare professional.