Cabergoline - A review of its efficacy in the treatment of Parkinson's disease

The dopamine agonist cabergoline has been most widely studied as an adjuvan t to levodopa/carbidopa therapy in patients with advanced Parkinson's disea se experiencing response fluctuations ('wearing-off' and 'on-off' phenomena ) to long term levodopa therapy. Significant improvements in Unified Parkin son's Disease Rating Scale (UPDRS) scores for motor function and activities of daily living were observed with cabergoline in a placebo-controlled stu dy in this patient group. In addition, cabergoline significantly reduced 'o ff' time compared with placebo after 12 and 24 weeks' therapy. The requirem ent for levodopa to control symptoms of Parkinson's disease is reduced in p atients given adjuvant cabergoline; however, the duration of this effect re mains unclear. To date, adjuvant cabergoline has been shown to control the symptoms of advanced Parkinson's disease for periods of up to 5 years in no ncomparative studies. Limited data indicate that cabergoline is at least as effective as bromocri ptine in this patient group, but is more effective than pergolide in contro lling certain disabilities associated with long term levodopa therapy (spec ifically nocturnal disabilities and motor function during the 'off' period) . In patients with early Parkinson's disease, de novo therapy with cabergolin e was associated with a significantly lower risk of developing motor compli cations after 5 years than de novo levodopa/carbidopa therapy in a single t rial. The incidence of motor complications (greater than or equal to 1)inpa tients randomised to receive cabergoline (+/- levodopa/carbidopa as require d) was 22.3 versus 33.7% in patients given only levodopa/carbidopa (p < 0.0 5). After 5 years, 64% of cabergoline recipients required additional levodo pa/carbidopa; however, the dosage was significantly lower than that given t o patients receiving only levodopa/carbidopa. UPDRS motor function scores w ere better in the levodopa/carbidopa group. The tolerability profile of cabergoline appears typical of a dopamine agoni st. CNS disturbances (including visual hallucinations, confusion, dizziness /light-headedness, increased libido, increased dyskinesias, insomnia and so mnolence) and gastric upset are the most common events, but are rarely seve re. Clinical trials indicate that the tolerability of cabergoline is simila r to that of bromocriptine, but may be better than pergolide. Conclusions: Cabergoline is useful for Controlling symptoms in patients wit h advanced Parkinson's disease experiencing response fluctuations to long t erm levodopa therapy. Importantly, it appears to be valuable as de novo the rapy in patients with early disease in terms of reducing the risk of motor complications. Its long elimination half-life (63 to 68 hours) and long dur ation of action, which allow once daily administration, may prove advantage ous in terms of attaining maximal symptom control.