Ergot alkaloids are derived from a fungus, Claviceps purpurea , which grows primarily on rye grain. The fungus forms a hard blackish body known as a sclerotium, which contains alkaloid compounds.
Central Nervous System effects
Ergot affects the central nervous system and in high levels can be toxic. Its central nervous system effects produce irritability, spasms, cramps, and convulsions. Because of its potentially harmful side effects, one ergot-based drug (Ergonovine or Ergotrate) was taken off the American market in 1993. Methylergonovine maleate (Methergine) is now the only ergot derivative in use in the United States.
It is given only as a uterine stimulant to control post-partum hemorrhage, PPH. Because of the risk of complications, and because the use of Methergine is contraindicated in many women, it has largely been replaced by the use of hormones prostoglandins, PGs and oxytocin as uterotonic agents.