Source and Composition. The leaves and tops of Lobelia inflata, (nat. ord. Lobeliaceae), a North American weed. It contains a liquid alkaloid, Lobeline,—also Lobelic Acid, Lobelacrin, resin, wax, etc.
Preparations and Doses.
- Tinctura Lobeliae, 20 p. c.—♏v-xxx.
- *Infusum Lobeliae,—Dose, ℨj-℥j.
- Extractum Lobeliae Fluidum,—♏j-x.
- *Lobelin (a resinoid),—gr. ss-gr. j.
Physiological Action. Lobelia has an acrid, nauseous taste, and a very unpleasant odor. It is expectorant, diaphoretic, purgative, emetic, anti-spasmodic and narcotic. It excites an abundant flow of saliva, much gastric mucus, and profuse urination and sweating; with nausea, vomiting, and great depression. The action of the heart is enfeebled, the blood pressure, at first increased, soon falls; muscular debility, reduced temperature ensue, then coma and death by paralysis of the respiratory centre. The motor nervous system is chiefly affected, especially the medulla oblongata and the nucleus of the pneumogastric contained therein.
Antagonists. Strychnine, Picrotoxin and Thebaine antagonize its action on the nervous system; the vaso-motor excitants, as Alcohol, Digitalis, Belladonna, oppose its effects on the circulation.
Therapeutics. Lobelia has gone out of fashion, yet it is useful in—
- Asthma,—a teaspoonful of the Tincture every 15 minutes until nausea ensues, gives decided relief in the paroxysm.
- Cough of dry, harsh character, with tickling in the throat and spasmodic dyspnoea,—Lobelia is an extremely effective expectorant.
- Constipation, from atony and deficient secretion,—a ten-minim dose of the Tincture at bed-time is excellent.
- Impaction of the Caecum, before inflammation occurs,—two-drop doses of the Tincture every hour will often relieve the obstruction.
- Strangulated Hernia,—The Infusion as an enema is much safer than Tobacco, and fully as efficient; but other laxatives are better.
- Poison-oak- Eczema,—an infusion (℥j to the pint) locally, is efficient.
- As an Emetic,—Lobelia is entirely too depressant to be given to children.
A Compend of Materia Medica, Therapeutics, and Prescription Writing, 1902, by Sam'l O. L. Potter, M.D., M.R.C.P.L.