192 ATROPINE. 



ATROPINE. 



Atropine (CiTH^sNOg == 287.04) is an alkaloid derived from the leaves and 



root of Atropa Belladonna, the Deadly Nightshade. 

 Pharmacodynamics. 

 Central Nervous System. Atropine primarily stimulates the motor divisions of 



the brain, thence the medulla and cord ; this is followed by marked depression tending 



towards paralysis. 



Unstriped muscle is made less responsive, probably because of a paralysis at the 



myoneural junction. 



Respiration. Centric stimulation quickens and deepens respiration; secondary 



depression produces slow, shallow breathing. 



Heart. Atropine paralyzes the inhibitory terminations of the vagus in the heart, 



thereby quickening heart action, and making it less efficient. 



Blood-pressure usually rises owing to stimulation of splanchnic constrictors. 



Large doses may lower B. P. through heart action. 



Eye. Pupil is dilated through paralysis of myoneurals of circularis muscle; 



muscle of accommodation also paralyzed. 



Alimentary Tract. Secretions lessened, and activity diminished, because of de- 

 pression of terminal filaments of vagus. 



Secretory Glands. Depressed through paralysis of terminations of secretory fibers. 



Metabolism markedly increased (Edsall). 



Temperature is often elevated; means unknown; possibly centric. 



Absorption is rapid from mucosa and subcutaneous tissues. 



Excretion. Atropine is largely oxidized in the tissues. Small amounts may 



escape in the urine. 



Local Action. Atropine depresses the sensory endings in the skin. 

 Tolerance. Rapidly acquired by rabbits; very little by man. 

 Symptoms. 



Therapeutic Doses. Toxic Doses. 



Oral and faucial dryness. Symptoms of small doses plus 



Dilatation of pupil. thirst and dysphagia; nau- 



Increased pulse. sea, headache and vertigo; 



Quickened respiration. widely dilated pupil, hoarse- 



Flushing of face and neck. ness and dysphonia ; weak, 



Restlessness. rapid, thready pulse; exag- 



Garrulity. gerated movements, hysteria 



Depression. and delirium, tremors (con- 



Lassitude, vulsions), depression, stupor, 



coma; death from asphyxia. 

 Therapeutics. 



Atropine may be used to lessen secretions; to relax spasm of the involuntary 

 muscles, especially of the intestines; to counteract depressions of the brain and me- 

 dulla; and as a diagnostic aid to ophthalmologists. 

 Dosage. 



Extractum Belladonnae Foliorum, 0.005 to -3 Gm. 

 Tinctura Belladonnas Foliorum, 0.3 to I mil. 

 Atropina, 0.0003 to 0.0008 Gm. 

 Atropinae Sulphas, same dose as for Atropina. 



Scopolamine, or Hyoscine, resembles closely the action of Atropine, except that 

 it depresses the central nervous system from the start. Hence, it is used in some 

 cases as a hypnotic. 



Dosage: Scopolamine Hydrobromide, 0.0003 to 0.0008 Gm. 



