Pramipexole Induced Complete Heart Block: A Case Report

Pramipexole is a dopamine agonist of non-ergoline class which is mainly used in the treatment of Parkinson's disease and restless leg syndrome. Fibromyalgia and depression are other off labelled indications. Adverse events like orthostatic hypotension, worsening of motor and psychiatric symptoms, confusion ,and drowsiness are often stated. Pramipexole induced cardiac events are often less likely, especially in those who doesn't had any underlying heart failure or renal impairment. We report a rare case of Pramipexole induced complete heart block which was observed in a 68 year old female who was admitted to the emergency department with syncope, generalised tiredness, and one episode of giddiness with blurring of vision. She had a history of depression but no history of any cardiac and renal disease. She was on a trial of pramipexole on suspicion of Parkinson's disease after which she developed complete heart block with intermittent atrioventricular block which was evident in the electrocardiogram (ECG). All alternative causes of AV block were ruled out. ECG returned to normal 24 hours after the withdrawal of pramipexole. A total of 7 reports have been found regarding Pramipexole induced cardiac failure. Among these, two reports from New Zealand are noted to have a causality score as 'unlikely'. Since Pramipexole causing AV block remains a blurred adverse effect, and the relative unawareness of this syndrome among the physicians, makes it a prudent topic to be reported. This case report gives emphasis on the importance of close monitoring, early detection and management of this adverse drug reaction based on current standard guidelines.