How Do Ergot Derivatives Work?

Ergot derivatives or ergot alkaloids are compounds initially derived from a fungal parasite ergot, Claviceps purpurea. These alkaloids are used to treat migraine headaches, increase uterine contractions during childbirth, and suppress prolactin secretion and vasoconstriction.

Ergot alkaloids are isolated from various Claviceps species and from other fungi and plants. However, some drugs are semisynthetic and are derived from naturally occurring ergot alkaloids, which include:

Natural ergot derivatives:

Ergotamine is a naturally occurring ergot derivative. It acts as a partial or complete agonist of serotonin receptors. It also interacts with adrenergic and dopamine receptors. Ergotamine is used to treat severe migraine attacks as it constricts intracranial blood vessels and inhibits the development of neurogenic inflammation. Ergotamine is also administered in combination with caffeine.

Ergometrine also known as ergonovine, a natural ergot derivative, is a direct stimulator of the uterine smooth muscle and increases the force and frequency of rhythmic contractions. Contraction of the uterine wall around bleeding vessels at the placental site produces hemostasis and prevents postpartum hemorrhage. It also induces cervical contractions. These stimulation effects may be associated with agonist or partial agonist effects at 5-hydroxytryptamine T2 receptors. Ergometrine may also produce arterial vasoconstriction by stimulating alpha-adrenergic and serotonin receptors and inhibiting the release of endothelial-derived relaxation factor. So, this drug is used as a noninvasive diagnostic aid to detect coronary vasospasm.

Semisynthetic Ergot Derivatives:

Dihydroergotamine is a derivative of ergotamine. It acts as an agonist of serotonin receptors and also interacts with adrenergic and dopamine receptors. It has high efficacy on 5-hydroxytryptamine receptor 1D and acts as an agonist and relieves migraine.

Methylergonovine is a semisynthetic ergot alkaloid derivative of ergonovine. It acts as an antagonist of dopamine D1 receptor and induces rapid and sustained uterine contractions, which shorten the third stage of labor and reduces blood loss.

Ergoloid mesylates drug is a mixture of three dihydrogenated ergot alkaloids. The mechanism of action is unclear, but it is thought to increase blood flow by reducing vascular tone and cerebral metabolism. It has both partial agonism and antagonism of adrenergic, dopaminergic, and serotonergic receptors. 

Ergot derivatives are given as intravenous or intramuscular injections, oral or sublingual tablets, suppository, and nasal spray. Ergot derivatives are used to:

• Increase uterine contractions
• Treat postpartum hemorrhage, a complication of abortion or childbirth
• Treat dementia
• Treat age-related cognitive impairment such as in Alzheimer’s disease
• Treat hyperprolactinemia
• Prevent vascular headaches such as migraine and histaminic cephalalgia also known as cluster headache (one-sided headache)
• Treat menopausal hot flashes

Side effects associated with ergot derivatives include:

• Nausea and vomiting
• Vertigo (spinning sensation)
• High blood pressure
• Low blood pressure
• Irregular heartbeats
• Coronary vasospasm
• Chest tightness or pain
• Tingling of fingers and toes
• Blurred vision
• Intermittent claudication (muscle pain, especially pain calf muscles with minimal exertion because of obstruction of arteries)
• Anaphylaxis (life-threatening allergic reactions)

The information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of ergot derivatives include:

• Dihydroergotamine (D.H.E. 45)
• Dihydroergotamine inhaled (Semprana)
• Dihydroergotamine intranasal (Migranal)
• Ergoloid mesylates (Hydergine)
• Ergometrine also known as ergonovine (Ergotrate)
• Ergotamine (Ergomar)
• Ergotamine/caffeine (Cafergot, Migergot)
• Methylergonovine (Methergine)