The effects of drugs on cough.

The pharmacologic treatment of cough can be divided into two main categories: therapy with controls, prevents or eliminates cough (i.e., antitussive) and therapy that makes cough more effective (i.e., pro-tussive). Definitive antitussive therapy depends on determining the aetiology or operant pathophysiologic mechanism and then initiating specific treatment; it can be almost uniformly successful. Non-specific antitussive therapy is directed at the symptom; it is indicated when definitive therapy cannot be given. For pathologic cough in man, predominantly studied in patients with chronic bronchitis, the following non-specific antitussive drugs have been shown to be effective: aerosolized ipratropium bromide, all narcotics of the phenanthrene alkaloid group (e.g., morphine and codeine), and the non-narcotics, dextromethorphan, glaucine, diphenhydramine, caramiphen, viminol and diviminol. Although studies have shown that hypertonic saline aerosol can improve cough clearance, there are no data, to date, that have convincingly demonstrated this agent or any other pro-tussive drug to be clinically useful.