Methylergonovine (Methergine) is used intravenously or in a tablet form after childbirth to help stop bleeding from the uterus. Methylergonovine belongs to the class of drugs known as ergot alkaloids. A drug in this class that is in wide use for the treatment of migraines is dihydroergotamine (DHE). DHE is one of the most effective drugs for the treatment of an acute migraine when given by injection.
Methysergide (Sansert) was another drug in this class and in a tablet form was used for the prevention of migraine and cluster headaches. It was very effective, but because of a very rare but serious side effect was withdrawn from the market. This was unfortunate because a small group of patients for whom other drugs were ineffective were glad to take that risk in exchange for significantly improved quality of life.
After the withdrawal of methysergide, the only oral ergot drug left on the market was methylergonovine and headache specialists continue to use it for their difficult to treat migraine and cluster patients. Methylergonovine was first reported to be effective for the treatment of migraines with medication overuse in an open-label trial of 60 patients in 1993. Of these 60 patients, 44 or 73% improved.
Another uncontrolled trial of methylergonovine in 20 cluster headache patients also showed it to be very effective. Intravenous infusion of this drug given to 125 migraine patients presenting to the emergency room provided pain freedom after one hour in 74%. This was also an uncontrolled, open-label study, which means that placebo effect very likely played a role.
This being an ergot alkaloid, we have to assume that its prolonged use also has the potential to cause serious side effects similar to methysergide. This side effect is fibrosis, or the development of scarring around kidneys, heart, or lungs. Even though it is very rare, this is a greatly feared side effect because it has no treatment and can lead to loss of function in kidneys, heart or lungs. It is speculated, but not proven, that stopping the drug for a month after 3 or 6 months of continuous use may prevent this side effect.
