Ergotamine, now used as a treatment for acute headaches, has medical history spanning several centuries, with mentions regarding its application in obstetrician practice from early 19th century. Ergotamine belongs to a family of ergot alkaloids, derived from ergot fungi, most notably the Claviceps purpurea fungus. This parasitic fungus grows on rye and other grain crops and the ergot alkaloids it produces can cause poisoning, called ergotism, in humans and animals. The symptoms of this poisoning reveal a lot about ergotamine pharmacology. Ergotism is usually associated with dry gangrene and a variety of adverse central nervous system effects such as spasms.
Ergotamine mode …show more content…
This is likely the effect of α-adrenoreceptor and 5-HT1B receptor agonism. The reason ergotamine was used in obstetrician practice was its potent uterotonic action, potentiating uterine contractions, thus help with childbirth, and its vasoconstrictive effect helps prevent post-partum bleeding. This practice is long discontinued as ergotamine has a potential to cause foetal damage, thus pregnancy is considered to be a contraindication. Therapeutic effects of ergotamine, which are the basis for headache treatment, are intracranial vasoconstriction via 5-HT1B receptor interaction and dural plasma extravasation inhibition, trigeminovascular pathway inhibition via the activation of 5-HT1D receptor. These actions best reduce the neurovascular event of migraines when they are long lasting non-frequent …show more content…
It exists in an aerosol form, useful for quick uptake into blood. Oral form, while the most common vector, exposes ergotamine to liver metabolism (in this case not entirely understood, yet high rate of first pass metabolism) and thus results in very low bioavailability, <1% of intravenous bioavailability. Ergotamine is also available in suppository form, with comparative bioavailability of 1-3%.
Clinical trials of ergotamine have raised a fair amount of controversy, as the drug has been in use long before proper clinical trial programmes were in place, the number of studies is very limited, methodology of some criticised, and the results contrary one to another. Studies of use of ergotamine as abortive treatment immediately upon onset of a migraine attack fall short of making a solid argument and quantify ergotamine efficacy. While it was superior to placebo in some trials in others it was worse. Overall, consensus is hard to reach on the dosage and efficacy of oral