Pergolide Mesylate

The dopamine D₂ receptor is a 7-transmembrane G-protein coupled receptor associated with G_i proteins. 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. Inhibition of MAPK appears to be mediated by c-Raf and B-Raf-dependent inhibition of MAPK/ERK kinase. 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. Ergoline alkaloids have been shown to have the significant affinity towards the 5-HT1 and 5-HT2 serotonin receptors, D1 and D2 dopamine receptors, and alpha-adrenergic receptors. This can result in a number of different effects, including vasoconstriction, convulsions, and hallucinations. Pergolide is a potent dopamine receptor agonist. It directly stimulates post-synaptic dopamine receptors at both D1 and D2 receptor sites in the nigrostriatal system. This can reduce the motor complications associated with Parkinson's. Agonism of 5-HT2B and 5-HT1B receptors is believed to be responsible for the fibrotic reactions and cardiac valvular disease associated with pergolide use. (A365, A2933, A2934, A2914, A2915, A2916)

Symptoms of pergolide overdose include nausea, vomiting, convulsions, decreased blood pressure, and CNS stimulation. Convulsive ergotism can cause painful seizures and spasms, diarrhea, paresthesias, itching, headaches, nausea and vomiting. Usually the gastrointestinal effects precede the central nervous system effects. As well as seizures there can be hallucinations and mental effects including mania or psychosis. Gangrenous ergotism causes dry gangrene as a result of vasoconstriction induced in the more poorly vascularized distal structures, such as the fingers and toes. Symptoms include desquamation, weak periphery pulse, loss of peripheral sensation, edema and ultimately the death and loss of affected tissues. (L1920, L1570)

Drug Induced Liver Injury Rank (DILIrank 2.0)

Pergolide mesylate

Ambiguous-DILI-concern

3

Adverse reactions

DOI:10.1016/j.drudis.2016.02.015