Completely metabolized by the liver, primarily by hydrolysis of the amide bond to produce lysergic acid and a peptide fragment, both inactive and non-toxic. Bromocriptine is metabolized by cytochrome P450 3A4 and excreted primarily in the feces via biliary secretion.
Bromocriptine has known human metabolites that include 5-bromo-N-[2,11-dihydroxy-7-(2-methylpropyl)-5,8-dioxo-4-propan-2-yl-3-oxa-6,9-diazatricyclo[7.3.0.02,6]dodecan-4-yl]-7-methyl-6,6a,8,9-tetrahydro-4H-indolo[4,3-fg]quinoline-9-carboxamide and 5-bromo-N-[2,10-dihydroxy-7-(2-methylpropyl)-5,8-dioxo-4-propan-2-yl-3-oxa-6,9-diazatricyclo[7.3.0.02,6]dodecan-4-yl]-7-methyl-6,6a,8,9-tetrahydro-4H-indolo[4,3-fg]quinoline-9-carboxamide.
Completely metabolized by the liver, primarily by hydrolysis of the amide bond to produce lysergic acid and a peptide fragment, both inactive and non-toxic. Bromocriptine is metabolized by cytochrome P450 3A4 and excreted primarily in the feces via biliary secretion.
Route of Elimination: Parent drug and metabolites are almost completely excreted via the liver, and only 6% eliminated via the kidney.
Half Life: 2-8 hours
The dopamine D<sub>2</sub> receptor is a 7-transmembrane G-protein coupled receptor associated with G<sub>i</sub> proteins. In lactotrophs, stimulation of dopamine D<sub>2</sub> receptor causes inhibition of adenylyl cyclase, which decreases intracellular cAMP concentrations and blocks IP3-dependent release of Ca<sup>2+</sup> 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 D<sub>2</sub> 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. Bromocriptine acts by directly stimulating the dopamine receptors in the corpus striatum. (A2914, A2915, A2916, A2941)
Bromocriptine has been reported to cause serum aminotransferase elevations in a small proportion of patients, but these abnormalities are usually mild, asymptomatic and self-limiting even without dose adjustment. In rare instances, more marked elevations occur that may require dose modification or discontinuation and which can recur with rechallenge. In addition, bromocriptine has been implicated in a small number of cases of clinically apparent acute liver injury, but the clinical characteristics and typical pattern of enzyme elevations has not been characterized and case reports of hepatic injury due to bromocriptine have not been published. Thus, bromocriptine is a very rare cause of clinically apparent liver injury and has not been implicated in causing acute liver failure or chronic liver injury.
Approximately 28% of the oral dose is absorbed; however due to a substantial first pass effect, only 6% of the oral dose reaches the systemic circulation unchanged. Bromocriptine and its metabolites appear in the blood as early as 10 minutes following oral administration and peak plasma concentration are reached within 1-1.5 hours. Serum prolactin may be decreased within 2 hours or oral administration with a maximal effect achieved after 8 hours. Growth hormone concentrations in patients with acromegaly is reduced within 1-2 hours with a single oral dose of 2.5 mg and decreased growth hormone concentrations persist for at least 4-5 hours.
来源:DrugBank
吸收、分配和排泄
消除途径
原药和代谢物几乎完全通过肝脏排泄，仅有6%通过肾脏消除。
Parent drug and metabolites are almost completely excreted via the liver, and only 6% eliminated via the kidney.
