Ergot alkaloids: Nursing pharmacology

Ergot alkaloids are a group of medications produced by the fungus Claviceps purpurea. Ergot alkaloids, or simply ergots, include methylergonovine, which can be used to prevent or treat postpartum hemorrhage.

Other ergots include ergotamine, which can be used to treat severe migraines, as well as bromocriptine, which can be used to treat Parkinson disease.Now, ergot alkaloids have similar structure to the neurotransmitters norepinephrine, serotonin, and dopamine.

As a result, they can act as antagonists on alpha-adrenergic receptors on smooth muscle cells, as well as agonists of serotonin and dopamine receptors, mainly found in the brain.

In particular, methylergonovine primarily acts on alpha-adrenergic receptors on the uterus, increasing the tone, and rate of uterine rhythmic contractions, as well as inducing vasoconstriction.

For this reason, methylergonovine can be administered intramuscularly, and less frequently orally or intravenously, usually after delivery of the placenta to decrease bleeding, and promote uterine involution.

Typically, methylergonovine is used as second-line after safer medications like oxytocin have failed to control the bleeding.

However, methylergonovine may cause significant side effects. The most common ones include gastrointestinal symptoms like nausea or vomiting, as well as abdominal pain and diarrhea.

Another important side effect is related to uterine hyperstimulation, where there’s too much contraction, and may result in uterine tetany.

Some clients may develop allergic reactions, such as a skin rash or swelling of the face, lips, or tongue; or present with headaches, dizziness, vertigo, and tinnitus.

Cardiovascular effects are mainly associated with intravenous administration, and include hypo- or hypertension, Raynaud phenomenon, palpitations, angina, and arrhythmias.

Ergot toxicity may cause ergotism, which mainly presents with nausea, vomiting and dyspnea; in addition, hypoperfusion of the limbs may lead to numbness, tingling, and muscle pain, or even gangrene involving the hands and feet.

And finally, ergotism may lead to sustained vascular spasms, seizures, hallucinations, and even coma.Now, methylergonovine is contraindicated in clients who have previously developed allergic reactions to ergot-derived medications.

In addition, due to its vasoconstrictive effects, methylergonovine is contraindicated in clients with cardiovascular disease, hypertension, preeclampsia, or eclampsia as well as during pregnancy, since it may stimulate contraction of the uterus and lead to decreased placental blood flow, premature labor, or even miscarriage.

Finally, because it is widely metabolized in the liver and excreted via urine, it should be used with caution in clients with hepatic or renal disease.Now, before administering methylergonovine, be sure there are no contraindications, such as hypertension or cardiovascular disease, or if the client is taking other medications that can increase the risk of serious side effects, such as alpha- or beta-agonists, triptans, azole antifungals, protease inhibitors, and certain macrolide antibiotics.

Methylergonovine is primarily administered IM in deep muscle mass. IV administration is used only in life-threatening situations, since it can cause a sudden onset of hypertension and increases the risk of coronary artery vasospasm, myocardial infarction, or stroke.

After administration, monitor the client’s vital signs closely, especially blood pressure and heart rate, as well as uterine tone, and the amount of vaginal bleeding present.

Also assess for signs of ergot toxicity. Finally, assess for the desired therapeutic effects of increased uterine tone and control of hemorrhage.Although methylergonovine is present in breast milk, breastfeeding appears to be safe in clients who receive methylergonovine in the immediate postpartum period.

When teaching clients receiving methylergonovine, remind them to report if they experience nausea, severe abdominal pain, numbness, or tingling of their extremities, or if they notice increased bleeding.

LO7Alright, as a quick recap… Methylergonovine is an ergot alkaloid that primarily acts on the alpha-adrenergic receptors in the uterine and vascular smooth muscle.This results in increased uterine tone and vasoconstriction, making it useful to control postpartum hemorrhage and promote uterine involution.

Methylergonovine is primarily administered IM. Side effects include hypertension, palpitations, headache, nausea, uterine hyperstimulation, allergic reactions, and ergotism.

There are several contraindications and cautions that should be considered before administering methylergonovine to clients, such as the presence of hypertension, cardiovascular disease, hepatic or renal disease, or if the client is taking certain medications that could increase the risk of side effects.