Cocaine (C17H21NO4 = 300.92) is an alkaloid derived from the leaves of Ery-throxylon coca, an indigene of South America.

Pharmacodynamics.

Central Nervous System. - Cocaine produces a brief primary descending stimulation, affecting first the cerebrum, then the hind brain, medulla, and cord. The stimulation is succeeded (often accompanied) by marked descending depression.

Muscular System. - Undetermined; possibly increased irritability.

Respiration is accelerated from centric stimulation, becoming progressively shallower and weaker; may show Cheyne-Stokes type.

Heart is accelerated, probably from local stimulation of accelerator fibers.

Blood-pressure is increased from vasoconstrictor stimulation, both centric and peripheral, and by more rapid heart action. Subsequent fall is due to local action on blood-vessels.

Eye. - Pupil is dilated from stimulation of dilator fibers; power of accommodation lessened, also intra-ocular tension.

Alimentary Tract. - Small doses stimulate, large ones inhibit, peristalsis by direct action on local nervous mechanism.

Secretory glands are slightly depressed. Kidneys often stimulated.

Metabolism. - Katabolism thought to be lessened slightly.

Temperature is increased, in poisoning, by action on center.

Absorption is rapid from mucosa and subcutaneous tissues.

Elimination. - Cocaine is largely oxidized in the tissues.

Local Action. - Cocaine produces loss of sensation through paralysis of those sensory nerve terminations that carry impressions of pain and touch. Applied to a nerve it interrupts all sensory impulses.

Tolerance is never more than partially acquired.

Symptoms.

Therapeutic Doses. Excitement.

Restlessness and garrulity. Accelerated pulse. Quickened respiration. Dilated pupil.

Headache and faucial dryness. Heightened reflexes.

Toxic Doses. Symptoms of small doses, plus excessive tachycardia, rapid dys-pneic breathing, possible convulsions, or fainting and collapse; then cyanosis and cold skin, slow, weak heart; weak, infrequent breathing; death from respiratory failure.

Symptoms arising from the cocaine habit are: digestive disturbances, emaciation, sleeplessness, tremors, hallucinations, disturbances of sensation and motion, delirium and insanity.

Therapeutics.

Cocaine has its chief utility as a local anaesthetic. Absorption, as thus used, may produce any of the above symptoms in cocaine-sensitive subjects.

Dosage.

Cocaine Hydrochloride, 4% solution for complete anaesthesia; 1% solution for analgesia; 6% solution on mucous membranes; 0.1% solution for infiltration; 1 mil of 2% solution for spinal anaesthesia.

Novocaine is a recently introduced synthetic substitute for Cocaine. It is considerably safer, though more fleeting in action.

Cocaine 66

Crimson = stimulation. Green = irritation. Violet = depression.