This section is from the book "Materia Medica And Therapeutics Inorganic Substances", by Charles D. F. Phillips. Also available from Amazon: Materia medica and therapeutics.
In the subacute and chronic stages, iodide of potassium, or of ammonium, relieves by an alterative action on the bronchial mucous membrane, thinning and ultimately diminishing the semi-purulent tough secretion. They may, sometimes with advantage, be combined with antispasmodics and other expectorants. In weakly subjects, the iodide of ammonium, in doses of from 2 to 5 gr. every four hours, may act better than the potassium salt. When there is an increase of temperature, aconite also should be given in doses of from 1 to 3 or 5 min. every two to four hours. If an expectorant is required, tartar emetic should be chosen. The dose should be small and frequent, and care should be taken to avoid emesis. With ordinary precaution in the regulation of the dose, neither aconite nor antimony need be dreaded for their depressing action, and it is remarkable how favorably these medicines act in conjunction with iodides.