Nalorphine has a mixed opioid agonist-antagonist properties. Nalorphine inhibits the cholinesterases of mouse brain, bovine erythrocytes and horse serum. It acts on mu-, k- and sigma-opioid receptors. Nalorfin by virtue of the agonistic effect has an analgesic effect but to a much lesser extent than morphine. Initially, before the appearance of a "pure" morphine-naloxone antagonist, nalorphine was used as an antidote for severe respiratory depression and other body function disorders caused by acute poisoning in case of an overdose of morphine, promedol, fentanyl or other narcotic analgesics, or with increased sensitivity to them. At present, nalorphine is practically not used for this purpose. It was replaced by naloxone. Large doses of nalorphine can cause nausea, cramps, drowsiness, headache, mental stimulation.