VERONAL, a crystalline substance extensively used in medicine as a hypnotic. Chemically, veronal is diethylmalonyl urea or diethyl-barbituric acid NHL,CO. It is pre pared by condensing diethylmalonic ester with urea in the presence of sodium ethylate, or by acting with ethyl iodide on the silver salt of malonyl urea; it forms a white crystalline powder, which is odourless, and has a slightly bitter taste. Its introduction followed the investigations of Emil Fischer and J. v. Merling on the pharmacological properties of certain open and closed ureides. Led thereto by the impression that hypnotic action appears to be largely dependent on the presence of ethyl groups, they prepared diethylacetyl urea, diethylmalonyl urea, and dipropylmalonyl urea. All three were found to be hypnotics: the first was about equal in power to sulphonal, whilst the third was four times as powerful, but its use was attended by prolonged after-effects. Veronal was found to be midway. It is best given
in cachets (I o to 15 grains). As it does not affect the circulatory or respiratory systems, or temperature, it can be employed in many diseased conditions of the heart and lungs as well as in mental disturbances, acute alcoholism, morphinomania and kidney disease. If taken during a prolonged period it seems to lose its effect. A soluble salt of veronal has been introduced under the name of medinal. Although the toxicity of veronal is low, the unreasonable consumption by persons suffering from insomnia has led to many deaths. (See BARBITURIC ACID.)