© 2007 American Thoracic Society
Restrict Empirical Use of Opiate Antitussives to Dry, Irritating Idiopathic CoughTo the Editor:I read with interest the article by Alyn H. Morice and colleagues wherein the authors have assessed the role of opiate therapy in reducing the severity of chronic cough (1). The probability-based approach to the diagnosis and treatment of chronic cough developed by the authors is highly appreciated (2). However, a few important aspects of opiate therapy in chronic cough merit further attention. The pattern of diagnoses in chronic cough varies with the referral population. In developing countries like India where tuberculosis and other infective diseases (such as Loeffler's syndrome) are rampant, such diagnoses should be seriously considered and ruled out before prescribing empirical morphine sulfate (3, 4). In the authors' previous study, there was no comment on eosinophilic bronchitis (2). Eosinophilic bronchitis may account for up to 10–15% of patients attending cough clinics (5). Some of the patients having eosinophilic bronchitis may have been wrongly diagnosed as having chronic treatment-resistant cough even though they would have responded very well to specific treatment (inhaled or oral corticosteroids). The cough was reported to be productive in 60% of the patients included in the present study (1). However, productive cough should usually not be suppressed, since retention of sputum in the tracheobronchial tree may interfere with the distribution of ventilation, alveolar aeration, and ability of the lungs to resist infection (6). Another limitation of this empirical approach is in patients with moderate to severe chronic obstructive pulmonary disease (COPD) in whom cough may persist and may not completely resolve with specific treatment. In such patients, the inadvertent prescription of morphine sulfate may even mask early symptoms and signs of acute exacerbation which may ultimately prove fatal. Long-term dependence is a concern with opiate therapy for a distressing mild, but non–life-threatening condition. Tolerance and dependence are of major concern especially in third-world countries where opiates can be procured over-the-counter without a prescription (7). A quarter of the patients in this study noted sedation, which means that the patients should be warned against driving or handling dangerous machinery. In patients with chronic cough, direct empiric therapy should be given in sequential and additive steps directed toward the most common etiologies of cough, because more than one cause of cough may be present. Empiric morphine sulfate should only be considered in the small subset of patients with dry, irritating, and disabling cough.
Christian Medical College and Hospital, Ludhiana, India FOOTNOTES Conflict of Interest Statement: A.S. has no financial relationship with a commercial entity that has an interest in the subject of this manuscript. Morice and colleagues declined to respond to this letter. REFERENCES
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