Physostigminum purum is used primarily as a miotic in glaucoma to constrict the pupil. Toxic effects include abdominal pain, nausea, hallucinations, and parasympathetic overstimulation. Large doses can cause muscle twitching, weakness, and respiratory paralysis. It increases salivary, gastric, and bronchial secretions, boosts intestinal movement, slows the heart, and dilates peripheral blood vessels. These effects can be counteracted by atropine.
