Expectorant Activity of Water in Acute Asthma Attacks

Abstract

THISHIS project was undertaken to find if water given by mouth has a pharmacological expectorant action in the sense that it is able to augment the output of demulcent respiratory tract fluid. Respiratory tract fluid is a secretion rich in soluble and insoluble mucus which can be collected through a cannula ligated into the trachea of an animal under certain conditions.1 An agent capable of increasing the output of this fluid may be said to have pharmacological expectorant activity.2 Therapeutic expectorant activity is present if the agent has the same properties at the dosage range and conditions of therapeutic use.Relatively few drugs reputed to be expectorants have been found to have pharmacological expectorant activity at doses near the range recommended in human therapy.2 This may be due in part to the fact that pharmacological expectorant activity has been found recently to vary with season.3 A drug studied in one season of the year might be found to have ex¬ pectorant activity which would be missed if studied in another season. Nevertheless, many pharmacologists and clinicians have concluded that expectorants are useless remedies. Statements to this effect appear in certain publications of organized medi¬ cine, for example that of the British Na¬ tional Formulary4 which concludes that "Cough mixtures . . . are probably (of) little more use than placebos." On the other hand, expectorants continue to be recommended particularly in the treatment of chronic cough, as in bronchial asthma,5·6 and of acute and chronic cough in infants and very young children,4 in which narcotic antitussives are contra¬ indicated and nonnarcotic antitussives may be ineffective.7The studies herein reported were prompted specifically by statements in the literature such as "Domestic remedies of honey in hot water with lemon juice . . . often give as much relief as more sophisti¬ cated mixtures." 4 Oral administration of aqueous solutions of sucrose 8 and volatile oils 9 had been previously found in this laboratory to have no effect in therapeutic doses on the volume output of respiratory tract fluid. This suggested that water itself might be an expectorant. Kendig " has stated that water is the most effective means of liquefying bronchial secretions in asthmatic children, and that it may be given by mouth or by steam inhalation. The inhalation of dry air into the trachea has been known for many years to dry the secretion of respiratory tract fluid, and this is remedied by substituting inhalation of humid air.2 No previous systematic study of the effect of oral administration of water has been reported. Materials and MethodsThe experiments were performed upon healthy male or nonpregnant female rabbits obtained from Canadian Breeding Laboratories, St. Con¬ stant, Quebec, Canada, and weighing 2 to 4 kg. They were fed rabbit pellets and water ad libitum and housed in animal cages, one rabbit per cage.Food was withdrawn for 48 hours to empty the stomach prior to administration of distilled water.The numbers of animals used are indicated ...