This section is from the "A Handbook of Useful Drugs" book, by State Medical Examining and Licensing Boards.
The ripe seed of Physostigma venenosum. Used commonly in the form of salts of its principal alkaloid, physostigmin (eserin).
Action and Uses: Physostigma stimulates the peripheral endings of the autonomous nerves and probably acts on the musculature to enhance its response to normal stimulation. It also depresses the action of the spinal cord. It greatly increases intestinal peristalsis. It slows the pulse and after large doses increases the blood-pressure. It produces contraction of the pupil by local action. When instilled into one eye it causes contraction of the pupil on that side and not on the other.
Physostigma is used for its depressing action on the spinal cord in tetanus, strychnin poisoning and other forms of convulsions. It should be used as an adjuvant to more powerful measures and not relied on as the sole remedy.
Physostigma is used to stimulate peristalsis in the paralytic form of colic and some cases of chronic constipation. It may be employed to overcome acute obstipation, provided there is no inflammation and no mechanical obstruction.
Physostigmin is used in treatment of eye diseases for the purpose of contracting the pupil and also to reduce intraocular tension. For the latter purpose it is serviceable in glaucoma. It is a useful remedy in peripheral ulcer of the cornea. It may be employed to hasten recovery from the effect of mydriatics, such as homatropin.