Appropriate use of antitussives and protussives. A practical review

As a symptom of an underlying condition, cough is one of the most common reasons patients see physicians. To the majority, a cough means that 'something is wrong' and it causes exhaustion and/or self-consciousness. Patients find these reasons as well as effects on lifestyle, fear of cancer and/or AIDS or tuberculosis to be the most troublesome concerns for which they seek medical attention. The treatment of cough can be divided into two main categories: (a) therapy that controls, prevents or eliminates cough (i.e. antitussive); and (b) therapy that makes cough more effective (i.e. protussive). Antitussive therapy can be either specific or nonspecific. Definitive or specific antitussive therapy depends on determining the aetiology or operant pathophysiological mechanism, and then initiating specific treatment. Since the cause of chronic cough can almost always be determined, it is possible to prescribe specific therapy that can be almost uniformly successful. Non-specific antitussive therapy is directed at the symptom; it is indicated when definitive therapy cannot be given. Practically speaking, the efficacy of nonspecific therapy must be evaluated in double-blind, placebo-controlled, randomised studies of pathological cough in humans. Such studies have demonstrated the efficacy of dextromethorphan, codeine and ipratropium bromide aerosol in patients with chronic bronchitis. While the preferred treatment for patients with cough due to angiotensin converting enzyme (ACE) inhibitor therapy is withdrawal of the offending drugs, it may be possible to ameliorate the cough by adding nifedipine, sulindac or indomethacin to the treatment regimen. The efficacy of protussive therapy has not been well documented. Although hypertonic saline aerosol and erdosteine in patients with bronchitis, and amiloride aerosol in patients with cystic fibrosis have been shown to improve mucus clearance, their clinical utility has not been adequately studied.