SULPHONAL GROUP, THE. This group of hypnotics includes sulphonal, methyl sulphonal known under the trade name of "trional" and ethyl sulphonal known as "tetronal," both of which are scheduled as poisons.
Sulphonal, or acetone diethyl sulphone (CH3)2C(S02C2/15)2, crystallizes in prisms melting at 125° C, which are practically insoluble in cold water, but dissolve in 15 parts of hot and also in alcohol and ether. It is the suiphondum of the B.P. and the sulphomethanum of the U.S.P. It is prepared by condensing acetone (q.v.) with ethyl mercaptan in the presence of hydro chloric acid, the mercaptol (CH3)2C(SC2H5)2 formed being sub sequently oxidized by potassium permanganate. Dose io to 3o grains. Trional (C1-13)(C21-15)C(S02C2115)2 is slightly more soluble in cold water than Sulphonal (1 in 32o). Dose io to 20 grains. Tetronal (C2H5)2C(S02C2H5)2 is less soluble in cold water than sulphonal (I in55o). Dose io to 20 grains. All three substances are white crystalline powders, odourless and almost tasteless.
Sulphonal was discovered by Baumann and introduced into med ical practice in 1888. The derivatives trional and tetronal were introduced soon afterwards. These drugs came into general use as hypnotics and were found specially valuable in calming motor excitement. They have been very largely used in mental cases and asylum practice. Their low solubility and slow absorption cause a delayed action. They have been recommended for calming the motor excitement in chorea, but great care is necessary if they are used for this purpose owing to the tender age of choreic patients and to the toxic action of the drugs.
Cumulative action may occur if the drugs are given in fre quently repeated doses since owing to the slow absorption a large quantity may accumulate in the alimentary tract. Absorption over a large area may then occur and give rise to toxic symptoms some time after the initial doses were administered. They should be taken with a large quantity of hot water about four hours before the time it is desired that sleep should ensue. Constipation should
be guarded against to avoid retention of the unabsorbed drug.
Owing to their slow absorption and consequent somewhat un certain and delayed action in producing sleep these drugs have in recent years become largely displaced by the barbituric acid (q.v.) hypnotics which have a rapid and more certain action.
Toxic Effects.—When first introduced it was thought that the sulphonal group were harmless hypnotics. But an overdose will cause a condition of deep stupor followed by loss of consciousness from which the patient cannot be roused (coma). This comatose condition may last some days and there is in this stage great danger of the development of fatal broncho-pneumonia.
Chronic sulphonal poisoning may follow the continued daily use of full therapeutic doses, and symptoms may occur which simu late organic disease of the nervous system. Thus headache, drowsi ness, vertigo and severe mental depression may result. The speech may become thick and articulation indistinct. The gait may become ataxic and reeling in type like that of alcoholic intoxication or cerebellar disease. Paralytic symptoms such as squint, ptosis, dip lopia, nystagmus or facial weakness may occur. Skin rashes have frequently occurred in patients who have been taking sulphonal in repeated doses; they may be of urticarial or erythematous type and are often associated with severe itching and irritation (pru rigo). Vesicular and bullous eruptions and purpura have been described. A common symptom of chronic sulphonal poisoning is the presence of altered blood pigment in the urine (haematopor phyrinuria), the urine becoming claret coloured. In some cases albumen and casts may appear in the urine due to the irritating action of the drugs on the kidneys. (W. H. WO Drug addiction (q.v.) is common. The mental depression not infrequently leads to the taking of a large overdose.