316 VEGETABLE DRUGS 



Action of Lobelia and Lobeline. 



Lobelia, or wild tobacco, resembles closely in action real tobacco. It 

 is a motor nerve paralyzant like conium, curare and tobacco. Again, 

 like tobacco, it exerts a stimulant action on the sympathetic ganglia and 

 causes vasoconstriction. Its degree of poisonous action is debatable. In 

 human medicine great depression and fatalities have occurred, especially 

 when vomiting does not follow large doses. There also appears to be a 

 difference in the strength of preparations. 



Toxic doses cause emesis, in animals capable of the act, purging, 

 prostration, feeble pulse, cold sweating, fall of blood pressure, coma, 

 collapse, and sometimes convulsions. Moderate doses injected into a 

 vein (lobeline), lead to fall of blood pressure and slow pulse, owing to 

 vagus stimulation (central and peripheral), and, later, accelerated pulse 

 and rise in blood pressure from stimulation of the vasoconstrictor ganglia. 

 Edmunds found that a heart arrested by muscarine will begin beating 

 again after the use of lobeline which appears, therefore, to stimulate the 

 heart muscle. Like tobacco it increases secretion by stimulation of the 

 sympathetic ganglia. Emesis is due to stimulation of the vomiting center 

 and local irritant action on the stomach. Purging is probably due to 

 stimulation of Auerbach's plexus and the drug is eliminated from the 

 blood by the stomach and intestines. Lobelia relaxes spasm of the bron- 

 chioles by depressing the bronchomotor nerves, and increases secretion 

 in its action as a nauseating expectorant. 



While it first stimulates the respiratory center, in poisoning the cen- 

 ter is paralyzed. Treatment in poisoning consists in the use of heart and 

 respiratory stimulants, as caffeine, camphor, atropine and strychnine with 

 heat externally. 



Uses, Internal. — Hypodermatic. — Lobelia is used infrequently in 

 human medicine and then only in bronchial asthma where it must be 

 pushed to its physiological limit to relax spasm. This results frequently 

 in femesis and is unpleasant. In bronchial asthma of dogs 20 minipis of 

 the tincture given every 16 minutes, till vomiting occurs, may give relief. 



It has not proved of value in heaves of horses. The therapeutic use 

 of lobeline depends directly upon its antispasmodic action in paralyzing 

 motor nerves and in its causing emesis. Lobeline sulphate (gr. l/lO) 

 combined in tablet (Abbott) with arecoline hydrobromide (gr.ss), and 

 strychnine sulphate (gr.l?^) has been found most successful in colic of 

 horses. Spasm and pain may be so quickly relieved that morphine will 

 not be required and at the same time catharsis secured. Lobeline is 

 especially favorable in colic in subjects of heaves as it relaxes the bron- 

 chioles while arecoline alone will increase dyspnea in these patients. 



Lobeline acts most satisfactorily in overcoming motor excitement in 

 azoturia or hemoglobinuria of horses, when given under the skin. 



In tetanus of horses lobeline may relieve muscular spasms so that the 

 animal is enabled to eat and drink, while it favors the action of cathartics. 

 Given in conjunction with antitoxin, the use of slings, and maintenance 

 of quiet and darkness, the drug has proven of great value. 



Lobeline appears to be a most useful antidote in strychnine poison- 



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