Chloral, or trichloraldehyde (C2HCI3O + H2O = 164.12), is obtained by treating absolute alcohol with chlorine.

Pharmacodynamics.

Central Nervous System. - Chloral depresses the receptive functions of the brain, renders less responsive the motor areas of the cortex, lowers reflex activity in the cord, and finally depresses the medulla.

Muscular System. - No direct action.

Respiration is rendered slightly slower and shallower. Ultimately it is paralyzed by centric action.

Heart is not affected by therapeutic doses. Toxic doses, by direct action on the heart muscle, cause a marked slowing, with auricular weakness and ventricular dilatation.

Blood-pressure affected by toxic doses only, when it is lowered by weak heart action and by paresis of the vasomotor center.

Alimentary Tract. - Irritation varies with concentration.

Metabolism. - Proteolysis augmented; fatty degeneration induced.

Temperature is reduced from lessened muscle activity, and from increased peripheral dissipation of heat.

Absorption. - Chloral is rapidly absorbed from the alimentary tract, and from the blood by the nerve cells.

Excretion takes place in the urine as urochloralic acid.

Local Action. - Irritant, becoming vesicant if concentrated.

Tolerance is soon acquired. Prolonged abuse of chloral leads to digestive disturbances, exanthemata, general depression, and cachexia, mental impairment, and fatty degenerations.

Symptoms.

Therapeutic Doses.

Drowsiness and weariness. Light somnolence. Quiet respiration and pulse. Effect lasts from 6 to 8 hours. Slight giddiness a sequence.

Toxic Doses.

Total unconsciousness. Muscle relaxation complete. Respiration slow and weak. Pulse slow and weak. Reflexes abolished. Contracted pupil. Cold, clammy skin. Paralysis of respiration.

Therapeutics.

Chloral is used to quiet nervous excitement, to induce sleep, and to relieve convulsions. Not an analgesic.

Dosage.

0.3 to 2 Gm., freely diluted.

Sulphonethylmethane and Sulphonmethane may be used in place of Chloral. They are attended with some danger, but show less after-depression, and usually produce as refreshing a sleep. Dose of either, 0.6 to 2 Gm.

Chloral Hydrate 62

Violet - depression.