190 COCAINE. 



COCAINE. 



Cocaine (C^EUiNC^ = 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 stimu- 

 lation, 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 shal- 

 lower 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 sen- 

 sory 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. Toxic Doses. 



Excitement. Symptoms of small doses, plus ex- 



Restlessness and garrulity. cessive tachycardia, rapid dys- 



Accelerated pulse. pneic breathing, possible con- 



Quickened respiration. vulsions, or fainting and col- 



Dilated pupil. lapse; then cyanosis and cold 



Headache and faucial dryness. skin, slow, weak heart ; weak, 



Heightened reflexes. infrequent breathing; death 



from respiratory failure. 

 Symptoms arising from the cocaine habit are: digestive disturbances, emacia- 



tion, sleeplessness, tremors, hallucinations, disturbances of sensation and motion, de- 



lirium 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; i% solution 

 for analgesia; 6% solution on mucous membranes; 0.1% solution for 

 infiltration; I mil of 2% solution for spinal anaesthesia. 



Novocaine is a recently introduced synthetic substitute for Cocaine. It is consid- 

 erably safer, though more fleeting in action. 



