Hedonal

HEDONAL, C₆H₁₃NO₂, Hedonalum, NH₂.CO.O.CH(CH₃)C₃H₇, methyl-propyl-carbinol urethane, i.e., the ester of carbamic acid and methyl-propyl-carbinol. It is produced by the action of ammonia on the chloroformic ester of methyl-propyl-carbinol [O.CO.O.CH(CH₃)C₃H₇], which in turn is obtained through the action of phosgene (COCl₂) on methyl-propyl-carbinol [CH₃(C₃H₇)CHOH]. A colorless crystalline powder with a weak spicy odor and a taste slightly resembling peppermint. Melting point 79°; sparingly soluble in cold water, more easily in hot water, and readily in alcohol, ether, and chloroform. At 37°, solubility in water is about 0.8%. It should be stored with care in a well-stoppered jar. Hedonal acts similarly to its lower homologue, urethane, depressing the central nervous system starting from its higher centers. It is oxidized in the body into carbon dioxide, water, and urea. The amide group contained in the molecule is credited with a certain stimulating effect on the medulla oblongata and the heart. On the other hand, the incorporation into the molecule of methyl-propyl-carbinol—a higher homologue than the ethyl radical—explains the stronger hypnotic effect of hedonal compared to urethane. Hedonal affects the heart so weakly that, according to animal experiments, cardiac activity is not noticeably weakened during complete hedonal anesthesia (see) almost until the very moment of respiratory arrest; the latter, in toxic doses, is the cause of death. The drop in blood pressure observed with large doses depends chiefly on paralysis of the vasomotor center. Although gas exchange decreases during hedonal sleep, it drops significantly less than with the use of chloral hydrate and other hypnotics, with the exception of urethane. According to the observations of some authors, hedonal possesses a diuretic effect, which is denied by others. Hedonal is readily prescribed for insomnia of neurasthenic and hysteric origin and, in view of its weak action on the heart, for insomnia in cardiac patients. In states of severe agitation (for example, in delirium tremens), the hypnotic effect of hedonal is unreliable. Hedonal does not cause harmful consequences even with prolonged use. Of the side effects, polyuria is observed most frequently, perhaps depending on the diuretic effect of urea formed from hedonal. Large doses sometimes cause transient albuminuria. In addition, eructation, nausea, and headache may occur as a consequence of taking hedonal. Hedonal is used (in warm water, due to its poor solubility) as a hypnotic at 1.0–1.5 (!) per dose, 3.0 per day, per orally in powders, cachets, and solution, as well as in the form of enemas. Sleep occurs after ¹/₂–1 hour and lasts 5–7 hours. Subcutaneous administration is not recommended due to the low solubility of hedonal and its irritating properties. Hedonal is also used in eclampsia (enemas up to 3.0). In addition, hedonal was proposed by Kravkov for mixed anesthesia with chloroform, with Kravkov proposing two methods: 1) intake of 1.0–3.0 of hedonal per os an hour before the operation and chloroform administration while simultaneously drinking lukewarm water (respectively tea) and 2) intravenous administration of 0.75% hedonal in heated physiological solution, which is done very slowly to avoid a sudden mass effect of hedonal on the nervous system. With both methods of administration, anesthesia sets in very quickly after the start of chloroform administration, and the excitation period is poorly expressed. The amount of chloroform required in these cases to induce and maintain anesthesia is significantly less than with chloroform alone. After the operation, patients feel calmer and suffer little from postoperative pain (see also General Anesthesia).