Colchicine. I. General pharmacology.

Acute actions of colchicine are characterized by a delayed appearance of effects, severe gastrointestinal disturbances, and delayed death. At death the body temperature falls drastically, functional changes in the nervous system are apparent, and the respiration fails. Physiological experiments indicate that the gastrointestinal effects are neurogenic. Other acute actions of colchicine include minor effects on the heart, elevated blood pressure due to arterial constriction induced by medullary stimulation, and potentiation of excitatory effects of sympathomimetic drugs on the circulation and nictitating membrane. Chronic administration of colchicine produces atrophy and weakness of the skeletal musculature, apparently due to a peripheral action. Affected muscles show abnormal responses to acetylcholine and potassium which resemble those seen after chronic denervation. These phenomena may be related to metabolic changes produced by colchicine. The results emphasize that colchicine possesses many pharmacologic activities. Unfortunately the mechanism of action of the compound is largely unknown and further investigations are needed.