This section is from the book "A Practitioner's Handbook Of Materia Medica And Therapeutics", by Thos. S. Blair. Also available from Amazon: A Practitioner's handbook of Materia Medica and Therapeutics.
Lobelia, Indian Tobacco. This old-fashioned drug is not sufficiently appreciated by the "regular" physicians of to-day. In moderate and small doses it is an exceedingly valuable agent. The fluidextract is a good preparation, the average dose of which is 8 I. but a more uniform preparation is the ec. tr., which is made from the seed. It is equivalent to the fluidextract of the seed. The seed contains twice as much lobeline (the narcotic principle) as does the herb. They also contain a fixed oil. Emetic properties are not so marked in the preparations of the seed as in that of the whole plant; in consequence, physicians who have used only the U.S. P. preparations cannot apprehend the eclectic appreciation of this drug. I have stated that the average dose of the fluidextract is 8 I.. That is what the U. S. P. gives, and it is therefore not to be wondered at that two or three experiences with lobelia, used as thus directed, is usually all the practician cares for when we remember that 10 I. of this preparation is the emetic dose. The maximum dose of ec. tr. is 30 I.. In large doses (f.e., 10 I. ; ec. tr., 20 to 30 I.) lobelia is emetic and very depressing, with relaxation and a feeble pulse. Owing to its depressing respiration in a similar manner to tobacco, its use as an emetic is seldom justified except in sthenic conditions or in emergency.
In large medicinal doses not emetic (f.e., 7 or 8 I.; ec. tr., 10 to 20 I.) it is useful where there is nerve tension and a spasmodic tendency, with flushed face and contracted pupils. Thus, it is useful in spasmodic asthma during a paroxysm, in puerperal eclampsia, tetanus, the spasms of hydrophobia and strychnia poisoning, hysterical convulsions, angina pectoris, where the patient is not feeble, and in obstetric practice, where a rigid os and too great fullness of perineal tissue delay labor. In all these conditions judgment must be used, and these large doses not be often repeated. From large experience with this drug, I prefer the ec. tr., and find that capsicum in full doses administered with it overcomes depression. That was a combination of the old-time herb doctor, but it was a good one.
In moderate doses (f.e., I to 3 I.; ec. tr., 2 to 5 I., if at long interval; f.e., I I., or ec. tr., 2 I. or less, if given frequently) lobelia is indicated in oppressed breathing and in respiratory troubles of an irritating character. In spasmodic croup the dose may be gradually run up to the point of slight nausea, since children tolerate the drug well. In whooping cough and spasmodic coughs generally it is useful. In some cases of congestion of the lungs it is very effective. In many conditions of disease its use to relax the muscles is effective, and this is particularly true in sthenic fevers and some forms of malaria.
In small doses (f.e., 1/2 to I I.; ec. tr., I to 2 I.) lobelia, like narcotic agents generally, has a transient stimulating effect upon the nervouS system and augments the secretions. Its influence is directed largely to the sympathetic nervous system, and thus promotes secretion and nutrition. Because of this, alterative properties have been attributed to it, but these effects are too transient to class it as a true alterative. In these small doses it appears to promote digestion when there is a tendency to colic, and is a useful remedy with children. The homeopaths use it in dyspnea with good effect and in gastric disturbances caused by drunkenness. They also use the tincture of Lobelia syphilitica in cases of influenza with Eustachian catarrh and coryza. In the nervous prostration of influenza they use the Purple lobelia. The homeopathic tinctures, in doses of I or 2 I., are of some degree of utility in the indications noted, but the doses must be frequently repeated, and it must be remembered that febrile states are not met by these small doses. They relieve symptoms, and that is about all they do. These tinctures are much weaker than the f.e. or ec. tr.