Salicylic acid and salicin (q.v.) share the properties common to the group of aromatic acids, which, as a group, are antiseptic without being toxic to man - a property practically unique; are unstable in the body; are antipyretic and analgesic; and diminish the excretion of urea by the kidneys.
In medicine antipyrine ("phenazonum") has been used as an analgesic and antipyretic. The dose is 5-20 grs., but on account of its depressant action on the heart, and the toxic effects to which it occasionally gives rise, it is now but little used.
Radium is analgesic and bactericidal in its action.
The external uses of the drug are mainly analgesic. The liniment or plaster of belladonna will relieve many forms of local pain.
Morphine is an analgesic and hypnotic, relieving pain and producing deep sleep. As contrasted with opium it differs in being less astringent and constipating.
In pill, and is said to be analgesic and haemostatic in its action.
Often it relieves vomiting, though in a few persons it may cause vomiting, but in far less degree than apomorphine, which is a powerful emetic. Opium has a more marked diaphoretic action than morphine, and is much less certain as a hypnotic and analgesic. There are a few therapeutic indications for the use of opium rather than morphine, but they are far less important than those which make the opposite demand.
Quinine has some analgesic power, and is a safe and often efficient drug in the treatment of neuralgia, even when the patient has not had malaria.