HYDROGENATED ERGOT ALKALOIDS
Clinical safety rating: caution
Comprehensive clinical and safety monograph for HYDROGENATED ERGOT ALKALOIDS (HYDROGENATED ERGOT ALKALOIDS).
Hydrogenated ergot alkaloids act as partial agonists/antagonists at α-adrenergic receptors, serotonergic (5-HT1B/1D) receptors, and dopaminergic receptors. They cause vasoconstriction by activating α-adrenoceptors and 5-HT receptors on vascular smooth muscle, and inhibit prolactin secretion via D2 receptor agonism.
| Metabolism | Metabolized primarily by CYP3A4 to active metabolites (e.g., 8'-hydroxy-dihydroergotamine). |
| Excretion | Primarily hepatic metabolism (70-80%) with biliary excretion; renal excretion accounts for less than 10% of unchanged drug. |
| Half-life | 2-3 hours for dihydroergotamine; 12-15 hours for ergoloid mesylates, requiring cautious dosing in hepatic impairment. |
| Protein binding | 65-70% bound to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Approximately 1.5-2.0 L/kg, indicating extensive tissue distribution. |
| Bioavailability | Oral: <1% due to extensive first-pass metabolism; Sublingual: 5-10%; Intramuscular: 40-60%; Intravenous: 100%. |
| Onset of Action | Oral: 30-60 minutes; Sublingual: 15-30 minutes; Intramuscular: 5-15 minutes; Intravenous: 1-5 minutes. |
| Duration of Action | Oral/Sublingual: 4-6 hours; Intramuscular: 3-4 hours; Intravenous: 2-4 hours. |
1 mg orally three times daily, or 0.3 mg intramuscularly or subcutaneously once daily.
| Dosage form | TABLET |
| Renal impairment | GFR <30 mL/min: avoid use; GFR 30-50 mL/min: caution, dose not well established. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: use with caution; Child-Pugh C: contraindicated. |
| Pediatric use | Not recommended for use in children; safety and efficacy not established. |
| Geriatric use | Lower initial dose recommended due to increased sensitivity; monitor for cognitive and cardiovascular effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for HYDROGENATED ERGOT ALKALOIDS (HYDROGENATED ERGOT ALKALOIDS).
| Breastfeeding | Contraindicated during breastfeeding. Ergot alkaloids suppress prolactin and may reduce milk production; M/P ratio is not established. Potential for infant toxicity (vomiting, diarrhea, seizures) and ergotism. Avoid breastmilk for at least 72 hours after last dose if administration is necessary. |
| Teratogenic Risk | Hydrogenated ergot alkaloids are contraindicated in pregnancy due to their oxytocic and vasoconstrictive properties. First trimester: potential for uteroplacental insufficiency and miscarriage. Second and third trimesters: risk of uterine hyperstimulation, fetal distress, prematurity, and neonatal ergotism. Category X. |
■ FDA Black Box Warning
Boxed warning: Serious and/or life-threatening peripheral ischemia has been associated with coadministration of ergot alkaloids with potent CYP3A4 inhibitors (e.g., protease inhibitors, macrolide antibiotics) or ergotism due to acute overdose.
| Common Effects | Skin peeling Itching Stinging sensation Erythema skin redness Edema swelling |
| Serious Effects |
Absolute: concomitant use with strong CYP3A4 inhibitors (e.g., clarithromycin, ritonavir), uncontrolled hypertension, ischemic heart disease, peripheral vascular disease, severe hepatic/renal impairment, pregnancy, lactation, hypersensitivity to ergot derivatives. Relative: hemiplegic or basilar migraine.
| Precautions | Risk of ergotism (vasospasm, ischemia, gangrene) with overdose or CYP3A4 inhibition; coronary vasospasm in patients with CAD; caution in sepsis, hypertension, hepatic/renal impairment; avoid prolonged use. |
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| Fetal Monitoring | Monitor maternal blood pressure, uterine tone (palpation), fetal heart rate, and signs of ergotism (nausea, muscle pain, paresthesia). Assess for symptoms of vasospasm (cyanosis, pulselessness). Serial fetal ultrasound for growth restriction if inadvertent exposure. |
| Fertility Effects | Ergot alkaloids are dopaminergic agonists; they may suppress prolactin secretion, leading to inhibition of lactation and potential disruption of menstrual cycle and ovulation. Use may cause amenorrhea, galactorrhea, or infertility, usually reversible upon discontinuation. |