LOBELIA. 279 



LOBELIACE.E. 



Lobelia LOBELIA. The dried flowering herb of 

 Lobelia inflata. Imported from North America. 



Characters. Stem angular ; leaves alternate, ovate, toothed, 

 somewhat hairy beneath ; capsule ovoid, inflated, ten-ribbed ; 

 herb acrid. Usually in compressed rectangular parcels. 



Composition. Lobelia contains an active principle, lobelina, 

 an oily, liquid, and volatile alkaloid, with a pungent taste, 

 and an odour like tobacco. It forms salts with acids. Lobelic 

 acid is united with the lobelina. 



Incompatibles. The caustic alkalies, which decompose 

 lobelina. 



Preparations. 



1. Tinctura Lobelias. 1 in 8 Proof Spirit. Dose, 10 to 30 min. 



2. Tinctura Lobelias JEtherea, 1 to 8 Spirit of Ether. Dose, 



10 to 30 min. 



ACTION AND USES. 

 1. IMMEDIATE LOCAL ACTION AND USES. 



Lobelia is a gastro-intestinal stimulant ; in large doses an 

 irritant, causing vomiting, pain, purging, and the ordinary 

 symptoms of depression. It is not to be used as an emetic, but 

 is sometimes useful in obstinate constipation. 



2. ACTION ON THE BLOOD, AND SPECIFIC ACTION AND USES. 



The active principles of lobelia appear to enter the blood 

 and tissues, where severe specific effects are produced by free 

 doses, including general depression, muscular tremors and 

 weakness, giddiness, headache, failure of the heart and 

 breathing, and cold perspiration: a condition resembling col- 

 lapse. The exact mode of the action of the drug is not known, 

 but it appears to depress the convolutions secondarily only ; to 

 lower the activity of the motor centres in the cord, and 

 cause muscular relaxation : to depress the respiratory centre, 

 and relax the bronchial muscles ; and to diminish the 

 force of the heart and the tension of the vessels, after brief 

 increase of the latter. Lobelia kills through the respiratory 

 centre, like its ally, tobacco, and not through the heart. 



Lobelia is a favourite remedy with some practitioners for 

 the paroxysm of asthma, for which it should be given at the 

 commencement in doses of 1 drachm of the Tincture, repeated 

 every fifteen minutes till nausea is produced. In 10 min. 

 doses it is a useful addition to expectorant mixtures for bron- 

 chitis with spasm and very scanty tough sputum. 



