Methergine is a tradename for methylergovovine, which is usually
classified as an oxytocic agent (i.e., an agent formerly used to
induce labor and currently to halt post-partum uterine bleeding.)
It’s an ergot derivative, but whereas ergotamine has a cyclic peptide
hanging off of the lysergic acid moiety, methylergonovine is a simple
lysergic acid amide.

I know that this and a related drug ergonovine do seem to have some
use by neurologists in the treatment of migraine, though I must confess
I’m not really up on its use for this indication (such use is off-label–
the FDA approved labelling simply talks about methylergonovine
as an oxytocic.  This isn’t necessarily worrisome, since a drug’s
clinical use almost always outpaces its FDA approved labelling.)

However, one drug which _is_ used as migraine prophylaxis is
methysergide (Sansert), and that’s simply methylergonovine with an
extra methyl group on the indole nitrogen.  Recent research has
suggested that methysergide is actually a pro-drug which is rapidly
converted to methylergovovine once ingested.  This might suggest that
methylergonovine could itself be useful as a prophylactic agent.
Long-term uninterrupted use of methysergide can cause fibrosis;
therefore, it would not be unreasonable to assume that similar
chronic use of methylergonovine might have a potential for this
side effect, at least in the absence of wider experience with
using the drug for this indication.  I’m talking _completely_ off
the top of my head here, which is why I’m adding sci.med to the
newsgroups distribution list, where neurologists like Dr. Nye
can see it and potentially offer a few more informed comments.

–
Steve Dyer
d…@ursa-major.spdcc.com