indication

Used to treat postpartum haemorrhage and postabortion haemorrhage in patients with uterine atony.

pharmacology

Ergonovine belongs to the group of medicines known as ergot alkaloids. These medicines are usually given to stop excessive bleeding that sometimes occurs after abortion or a baby is delivered. They work by causing the muscle of the uterus to contract.

mechanism of action

Ergonovine directly stimulates the uterine muscle to increase force and frequency of contractions. With usual doses, these contractions precede periods of relaxation; with larger doses, basal uterine tone is elevated and these relaxation periods will be decreased. Contraction of the uterine wall around bleeding vessels at the placental site produces hemostasis. Ergonovine also induces cervical contractions. The sensitivity of the uterus to the oxytocic effect is much greater toward the end of pregnancy. The oxytocic actions of ergonovine are greater than its vascular effects. Ergonovine, like other ergot alkaloids, produces arterial vasoconstriction by stimulation of alpha-adrenergic and serotonin receptors and inhibition of endothelial-derived relaxation factor release. It is a less potent vasoconstrictor than ergotamine. As a diagnostic aid (coronary vasospasm), ergonovine causes vasoconstriction of coronary arteries.

toxicity

The principal symptoms of overdose are convulsions and gangrene. Other symptoms include bradycardia, confusion, diarrhoea, dizziness, dyspnoea, drowsiness, fast and/or weak pulse, miosis, hypercoagulability, loss of consciousness, nausea and vomiting, numbness and coldness of the extremities, pain in the chest, peripheral vasoconstriction, respiratory depression, rise or fall in blood pressure, severe cramping of the uterus, tachycardia, tingling, and unusual thirst.

biotransformation

Hepatic.

absorption

Absorption is rapid and complete after oral or intramuscular administration.

half life

t_{1/2 α}=10 minutes; t_{1/2 β}=2 hours

route of elimination

Thought to be eliminated by non-renal mechanisms (i.e. hepatic metabolism, excretion in feces)

drug interactions

Acebutolol: Ischemia with risk of gangrene

Almotriptan: Possible severe and prolonged vasoconstriction

Atenolol: Ischmeia with risk of gangrene

Bisoprolol: Ischemia with risk of gangrene

Carvedilol: Ischemia with risk of gangrene

Delavirdine: The antiretroviral agent may increase the ergot derivative toxicity

Desvenlafaxine: Increased risk of serotonin syndrome. Monitor for symptoms of serotonin syndrome.

Efalizumab: The antiretroviral agent may increase the ergot derivative

Eletriptan: Possible severe and prolonged vasoconstriction

Epinephrine: Possible marked increase of arterial pressure

Erythromycin: Possible ergotism and severe ischemia with this combination

Esmolol: Ischemia with risk of gangrene

Frovatriptan: Possible severe and prolonged vasoconstriction

Isosorbide Dinitrate: Possible antagonism of action

Isosorbide Mononitrate: Possible antagonism of action

Labetalol: Ischemia with risk of gangrene

Metoprolol: Ischemia with risk of gangrene

Nadolol: Ischemia with risk of gangrene

Naratriptan: Possible severe and prolonged vasocontriction

Nitroglycerin: Possible antagonism of action

Oxprenolol: Ischemia with risk of gangrene

Phenylephrine: Possible marked increase of arterial pressure

Pindolol: Ischemia with risk of gangrene

Propranolol: Ischemia with risk of gangrene

Telithromycin: Telithromycin may reduce clearance of Ergonovine. Consider alternate therapy or monitor for changes in the therapeutic/adverse effects of Ergonivine if Telithromycin is initiated, discontinued or dose changed.

Timolol: Ischemia with risk of gangrene

Tipranavir: Tipranavir, co-administered with Ritonavir, may increase the plasma concentration of Ergonovine. Concomitant therapy is contraindicated.

Tramadol: Increased risk of serotonin syndrome. Monitor for symptoms of serotonin syndrome.

Tranylcypromine: Increased risk of serotonin syndrome. Use caution during concomitant therapy and monitor for symptoms of serotonin syndrome.

Trazodone: Increased risk of serotonin syndrome. Monitor for symptoms of serotonin syndrome.

Trimipramine: Increased risk of serotonin syndrome. Monitor for symptoms of serotonin syndrome.

Venlafaxine: Increased risk of serotonin syndrome. Monitor for symptoms of serotonin syndrome.

Voriconazole: Voriconazole, a strong CYP3A4 inhibitor, may increase the serum concentration of ergonovine by decreasing its metabolism. Concomitant therapy is contraindicated.

Zolmitriptan: Concomitant use of the serotonin 5-HT1D receptor agonist, zolmitriptan, and the ergot derivative, ergonovine, may result in additive vasoconstrictive effects. Concomitant use within 24 hours is contraindicated.