Mirapex (pramipexole), a medication used to treat patients with Parkinson’s disease, may raise the risk of developing heart failure, the FDA warned today in a public communiqué. Mirapex is also prescribed for people with restless leg syndrome.

The FDA (Food and Drug Administration) said that available data on Mirapex needs to be reviewed again in more detail.

After gathering and examining data from randomized trials, FDA assessors found that the incidence of heart failure was higher among patients on Mirapex compared to those on placebo. The Agency stressed that the difference was “not statistically significant”.

Because of limitations in the studies, it is very hard to decide whether higher heart failure rates was linked to Mirapex therapy or some other influencing factor(s).

The FDA cannot, with the data available and the study limitations, determine whether Mirapex really does raise the risk of heart failure. The Agency says it is working with the manufacturer, Boehringer Ingelheim Pharmaceuticals, Inc., to clarify what the risks of heart failure associated with Mirapex are. The public will be updated as soon as more information becomes available, the FDA added.

Doctors are being asked to carry on following the recommendations in the drug label when prescribing pramipexole. All patients on pramipexole should continue taking it according to their doctors’ instructions, the FDA urged. If you have any doubts concerning pramipexole, ask your health care professional.

Randomized placebo-controlled parallel phase two and three clinical trials that compared Mirapex to placebo were submitted to the FDA in 2008 and then again in 2010. These studies found that the rates of newly diagnosed heart failure were more common among the Mirapex patients. However, the difference was not a statistically significant one.

To determine whether there might be a link between Mirapex usage and heart failure, Boehringer Ingelheim sponsored an epidemiologic study that used the UK General Practice Research Database. This case-control study involved a cohort of anti-Parkinsonian medication users, aged from forty to eighty-nine years. The study matched 783 cases of heart failure to 7,454 controls. The study showed that those using any dopamine agonist, compared to patients using no dopamine agonist had a significantly higher risk of heart failure (risk ratio [RR] = 1.58; 95% confidence interval [CI]: 1.26-1.96).

Mirapex (pramipexole) is a dopamine agonist of the non-ergoline class which is primarily used for the treatment of early-stage Parkinson’s disease and restless leg syndrome. Off label, Mirapex is sometimes used for treating cluster headaches, and sexual dysfunction when it is a side effect of some types of antidepressants, such as SSRIs. Some pilot studies have found that Mirapex is better than placebo in controlling some of the symptoms of bipolar disorder. Mirapex is also being investigated for the treatment of fibromyalgia and depression.

The following common side effects have been reported by patients taking pramipexole:

    Written by Christian Nordqvist