This section is from the "A Handbook of Useful Drugs" book, by State Medical Examining and Licensing Boards.
The sclerotium of Claviceps purpurea, replacing the grain of rye. Ergot appears to owe its activity to two active principles, ergotoxin (hydroergotinin) and hydroxyphenyl-ethylamin. The latter substance is closely related to epinephrin both in composition and in pharmacologic action.
Action and Uses : The several active principles of ergot have somewhat different actions, but the total effect is as follows:
Ergot causes powerful tonic, sometimes tetanic contractions of the uterus. It slows the pulse by stimulating the cardio-inhibitory centers. It also produces contraction of other involuntary muscles such as those of the blood-vessels, stomach and intestines, the bladder, etc. It seems to have a specially beneficial effect on acute congestions of the central nervous system.
Extreme and long-continued contraction of the blood-vessels, especially of the extremities, may lead to gangrene. Some animals do not show this action, while others are very susceptible.
The most common use of ergot is to prevent post-partum hemorrhage. For this purpose a full dose is often given as soon as the second stage of labor terminates, but it is much safer to give it after the placenta has been expelled. Its use during labor should be avoided as it may cause rupture of the uterus or asphyxia of the child. It is an effective remedy for "after-pains." Ergot is much used for hemorrhage from the uterus in menorrhagia and metrorrhagia. Its use for hemorrhage from other internal organs is not rational, as it increases blood-pressure and tends to prolong rather than check the bleeding.
It is asserted to be a good remedy for congestions in various regions. It has been recommended for the treatment of the early stage of acute pneumonia and also for pulmonary congestion in typhoid fever. It is at times useful in diabetes insipidus. In colliquative night-sweats due to relaxation of the blood-vessels, ergot is an efficient remedy.
Dosage: 2 gm. or 30 grains. It is sometimes administered in the form of powder
 
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