This name is applied to a chemical product of the same series as chloralamide, and they closely correspond in physiological action. Sulphonal occurs in colorless, tasteless, and odorless crystals, not freely soluble in cold water (1 to 100 or 150), but more freely in boiling water. It is best administered in powder, in wafer, or in capsule. The dose ranges from gr. v to gr. xxx.

Kast, who first investigated the properties of sulphonal, found it to be without toxic qualities; but the large clinical use made of the new hypnotic speedily revealed the fact that it may cause untoward symptoms, and already numerous deaths from it have been reported. It is not actively toxic. Very early attention was called to its dangers, when given in too large doses, by Morandon, Voisin, Falret, and others, and Dr. Petitt, of Dayton, reported a death from its administration to a melancholic after two doses of one gramme (15·4 grains) each. Toxic doses in animals cause death by coma and convulsions, preceded by disorder of muscular movements (Mairet, Knoblauch).

Sulphonal is a certain and comparatively safe hypnotic. To procure the best results from it, certain peculiarities of its action must be regarded. Its hypnotic effect develops somewhat slowly, and from two to four hours elapse after it is taken before sleep comes on. Hence it should be administered early in the evening if it is desired to affect the patient the first part of the night. As the effects of sulphonal come on slowly, so in a corresponding degree they are apt to be prolonged. More or less drowsiness is experienced the next day after a single dose, and it often happens that sleep is better on the second night. Where the administration of sulphonal is rendered necessary for a continuous period, it often suffices to administer a sufficient dose on alternate nights. Combination with trional improves the action, and is often effective. If a dose of trional be administered at bed-hour, with sulphonal, the hypnotic action begins promptly, and is carried on through the after part of the night. Thus, sulphonal, gr. x; trional, gr. v. M. Ft. pulv. no. i. The existence of pain, or the febrile state, interferes with its action as a sleep-producer. It is not followed by unpleasant after-effects—by nausea, headache, hebetude of mind. As a hypnotic it has been largely used in asylum practice in all forms of chronic mental disorders characterized by insomnia, in paranoia, mania, and hallucinatory delusions caused by alcoholism, and in fevers, inflammatory diseases, and other acute and chronic maladies. Valvular disease of the heart does not contraindicate its use.

As compared with chloral, sulphonal is rather more certain and far safer. It is more efficient and safer than chloralamide as a hypnotic merely, although its range of action is smaller