This section is from the book "Dental Medicine. A Manual Of Dental Materia Medica And Therapeutics", by Ferdinand J. S. Gorgas. Also available from Amazon: Dental Medicine.
Urethan is a combination of carbonic acid and ethylic ether. It occurs in white crystals, without odor, tasteless, and insoluble in water.
Urethan is a hypnotic which may be employed to cause quiet and sleep when the conditions are favorable to its action. It is similar to paraldehyde and has no irritating effect upon the stomach, nor does it impair digestion. Although insoluble in water, the fluids of the stomach dissolve it readily, and it promptly diffuses into the blood. The first effect of its action is stimulating, which is of brief duration, then a diminution of action, slowing of circulation and respiration, decline of temperature and weakening of the reflexes which finally disappear, then drowsiness and tranquil sleep, and, if the quantity given be toxic, coma and insensibility. Fifteen and one-half grains are held sufficient to cause sleep. It is not an analgesic, hence pain will prevent its hypnotic action. Unpleasant after-effects do not occur, except when stomachal troubles are present, and it is seldom that there is headache, nausea or vertigo. Sleep is produced in fifteen minutes to an hour, and continues from six to eight hours. It has been employed with benefit in epilepsy, chorea, spasms, cramp, delirium tremens, tetanus, etc. Its action upon digestion is as follows: a. Strong solutions - that is, 0.5 gramme, 0.25 gramme, 0.175 gramme - delayed digestion ; that the stronger the solution the greater was the delay.
b. Weak solutions - that is, 1, 2 and 3 milligrammes - neither delayed nor accelerated digestion.
c. Neither strong nor weak solutions retarded decomposition.