Drug information of Pergolide
Pergolide is a long-acting dopamine agonist approved in 1982 for the treatment of Parkinson’s Disease. It is an ergot derivative that acts on the dopamine D2 and D3, alpha2- and alpha1-adrenergic, and 5-hydroxytryptamine (5-HT) receptors.
It was indicated as adjunct therapy with levodopa/carbidopa in the symptomatic treatment of parkinsonian syndrome. It was later found that pergolide increased the risk of cardiac valvulopathy. The drug was withdrawn from the US market in March 2007 and from the Canadian market in August 2007.
Mechanism of effect
The dopamine D2 receptor is a 7-transmembrane G-protein coupled receptor associated with Giproteins. In lactotrophs, stimulation of dopamine D2 receptor causes inhibition of adenylyl cyclase, which decreases intracellular cAMP concentrations and blocks IP3-dependent release of Ca2+ from intracellular stores.
Decreases in intracellular calcium levels may also be brought about via inhibition of calcium influx through voltage-gated calcium channels, rather than via inhibition of adenylyl cyclase. Additionally, receptor activation blocks phosphorylation of p42/p44 MAPK and decreases MAPK/ERK kinase phosphorylation.
Dopamine-stimulated growth hormone release from the pituitary gland is mediated by a decrease in intracellular calcium influx through voltage-gated calcium channels rather than via adenylyl cyclase inhibition. Stimulation of dopamine D2 receptors in the nigrostriatal pathway leads to improvements in coordinated muscle activity in those with movement disorders.
Pergolide is a potent dopamine receptor agonist. Pergolide inhibits the secretion of prolactin in humans; it causes a transient rise in serum concentrations of growth hormone and a decrease in serum concentrations of luteinizing hormone. In Parkinson’s disease, Pergolide is believed to exert its therapeutic effect by directly stimulating post-synaptic dopamine receptors in the nigrostriatal system.
Absorption: Significant amount may be absorbed (evidence on bioavailability still lacking).
Protein binding: 90%
Metabolism: Extensively hepatic.
Administration of Pergolide tablets should be initiated with a daily dosage of 0.05 mg for the first 2 days. The dosage should then be gradually increased by 0.1 or 0.15 mg/day every third day over the next 12 days of therapy. The dosage may then be increased by 0.25 mg/day every third day until an optimal therapeutic dosage is achieved.
Pergolide tablets are usually administered in divided doses 3 times per day. During dosage titration, the dosage of concurrent l-dopa/carbidopa may be cautiously decreased.
Side effectsInsomnia , Diarrhea , nausea , flatulence , hallucinations , difficulty urinating , rhinitis
Concerns related to adverse effects:
Somnolence is a common occurrence in patients receiving Pergolide.
In clinical trials, approximately 10% of patients taking Pergolide with l-dopa versus 7% taking placebo with l-dopa experienced symptomatic orthostatic and/or sustained hypotension, especially during initial treatment. With gradual dosage titration, tolerance to the hypotension usually develops. It is therefore important to warn patients of the risk, to begin therapy with low doses, and to increase the dosage in carefully adjusted increments over a period of 3 to 4 weeks.
In controlled trials, Pergolide with l-dopa caused hallucinosis in about 14% of patients as opposed to 3% taking placebo with l-dopa. This was of sufficient severity to cause discontinuation of treatment in about 3% of those enrolled; tolerance to this untoward effect was not observed.
Points of recommendation
Because Pergolide may cause somnolence and the possibility of falling asleep during activities of daily living, patients should be cautioned about operating hazardous machinery, including automobiles, until they are reasonably.
Patients should be advised to notify their physician if they become pregnant or intend to become pregnant during therapy.
Patients should be advised to notify their physician if they are breast feeding an infant.