Pramipexole

BOEHRINGER INGELHEIM

Nonergot dopamine agonist approved for the treatment of primary restless legs syndrome

Pramipexole was approved on November 7, 2006, for the treatment of moderate-to-severe primary restless legs syndrome (RLS). This agent has high relative in vitro specificity and full intrinsic activity at the D₂ subfamily of dopamine receptors.

Safety. Patients treated with pramipexole have reported falling asleep during activities of daily living, including during the operation of motor vehicles, as late as 1 year after treatment initiation. Although some of these patients reported somnolence during pramipexole treatment, some patients perceived no excessive drowsiness before falling asleep during daily activities. Patients should be asked about any factors that could increase the risk of somnolence, such as the presence of sleep disorders and the use of sedatives or concomitant medications that could increase pramipexole plasma levels. Dopamine agonists have also been linked with orthostatic hypotension, especially during dose escalation. Pramipexole may cause or exacerbate dyskinesia. Cases of pathological gambling, hypersexuality, and compulsive eating have been reported in patients treated with dopamine agonists. Some patients treated with pramipexole have experienced rebound (shifting of symptoms from evening to early morning) or augmentation (earlier onset of symptoms, increase of symptoms, and spread of symptoms to additional extremities). The most commonly reported adverse events with pramipexole treatment include nausea, somnolence, fatigue, headache, and insomnia.

Dosing. The recommended starting dosage of pramipexole is 0.125 mg once daily 2 to 3 hours before bedtime. If patients do not experience symptom relief, the dose may be increased to 0.25 mg after 4 to 7 days, and then to 0.5 mg after another 4 to 7 days if necessary. The time between titration steps should be increased to 14 days in patients with moderate-to-severe renal impairment (creatinine clearance 20 to 60 mL/min).