PARLODEL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for PARLODEL (PARLODEL).
Dopamine D2 receptor agonist; inhibits prolactin secretion by binding to pituitary and hypothalamic D2 receptors.
| Metabolism | Primarily hepatic via CYP3A4; undergoes extensive first-pass metabolism. |
| Excretion | Renal: approximately 60% as metabolites, 6% as unchanged drug; biliary/fecal: approximately 40% as metabolites and unchanged drug. |
| Half-life | Terminal elimination half-life: 12-14 hours (biphasic, initial half-life 6-8 hours); clinical context: steady-state achieved in 2-3 days. |
| Protein binding | Approximately 90-96% bound to serum albumin. |
| Volume of Distribution | Vd: 3-5 L/kg (large, indicating extensive tissue distribution). |
| Bioavailability | Oral: approximately 28% (extensive first-pass metabolism). |
| Onset of Action | Oral: 30-60 minutes for prolactin-lowering effect; clinical effect on parkinsonism may take weeks. |
| Duration of Action | Prolactin-lowering effect: 8-12 hours after single oral dose; clinical effect in Parkinson's disease: sustained with chronic dosing. |
Parkinson disease: initial 1.25 mg orally twice daily, increase by 2.5 mg/day every 2-4 weeks; usual range 15-30 mg/day. Hyperprolactinemia: initial 1.25-2.5 mg orally once daily, titrate to 2.5 mg twice daily; maintenance 2.5-15 mg/day.
| Dosage form | TABLET |
| Renal impairment | CrCl <30 mL/min: reduce dose by 50%; CrCl <10 mL/min: avoid use. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: avoid use. |
| Pediatric use | Not recommended for children <2 years. Age 2-12: 0.05-0.1 mg/kg/day orally in divided doses, max 0.2 mg/kg/day. |
| Geriatric use | Initiate at lowest dose (1.25 mg once daily); increase slowly due to increased sensitivity and risk of orthostatic hypotension or confusion. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for PARLODEL (PARLODEL).
| Breastfeeding | Bromocriptine suppresses lactation by inhibiting prolactin secretion. It is contraindicated in breastfeeding women as it reduces milk production and may expose the infant to the drug. The milk-to-plasma (M/P) ratio is approximately 0.6. Safety in nursing infants has not been established; therefore, breastfeeding is not recommended during therapy. |
| Teratogenic Risk | Parlodel (bromocriptine) is classified as FDA Pregnancy Category B. There are no adequate and well-controlled studies in pregnant women. In animal studies, administration of bromocriptine during organogenesis produced post-implantation loss and decreased fetal weight at doses higher than human therapeutic doses. There is a risk of fetal harm if used during pregnancy, particularly in the first trimester, due to potential effects on prolactin and possible uterotonic effects. Use only if clearly needed and after careful risk-benefit assessment. |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to bromocriptine or ergot alkaloids","Uncontrolled hypertension","Preeclampsia/eclampsia","Breastfeeding (suppresses lactation)","Severe ischemic heart disease or peripheral vascular disease"]
| Precautions | ["May cause hypotension, particularly during initial dosing","Risk of fibrotic complications (e.g., cardiac valvulopathy, pulmonary fibrosis) with prolonged use","May impair mental and/or physical abilities; caution with driving","Potential for psychotic reactions in patients with Parkinson's disease","Should not be withdrawn abruptly; taper slowly"] |
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| Fetal Monitoring | Monitor blood pressure frequently, especially during initiation and dose escalation, due to risk of hypotension. Assess for symptoms of cerebrovascular accidents or cardiac arrhythmias. During pregnancy, monitor fetal growth and development via ultrasound. Monitor for signs of uterine contractions or bleeding. Periodic assessment of prolactin levels may be considered. |
| Fertility Effects | Bromocriptine restores ovulation and fertility in hyperprolactinemic patients by lowering prolactin levels. In women undergoing ovulation induction, there is an increased risk of multiple gestation. In men, it may improve sperm parameters and libido if hyperprolactinemia was the cause of infertility. No direct adverse effects on fertility have been reported at therapeutic doses. |