Important drugs for cough in advanced cancer.

Cough is a defense mechanism that prevents the entry of noxious materials into the respiratory system and clears foreign materials and excess secretions from the lungs and respiratory tract. In advanced cancer, it is a common symptom that interferes with the patient's daily activity and quality of life. Empiric treatment with antitussive agents is often needed. Two classes of antitussive drugs are available: (1) centrally acting: (a) opioids and (b) non-opioids; (2) peripherally acting: (a) directly and (b) indirectly. Antitussive availability varies widely around the world. Many antitussives, such as benzonatate, codeine, hydrocodone, and dextromethorphan, were extensively studied in the acute and chronic cough settings and showed relatively high efficacy and safety profiles. Benzonatate, clobutinol, dihydrocodeine, hydrocodone, and levodropropizine were the only antitussives specifically studied in cancer and advanced cancer cough. They all have shown to be effective and safe in recommended daily dose for cough. In advanced cancer the patient's current medications, previous antitussive use, the availability of routes of administration, any history of drug abuse, the presence of other symptoms and other factors, all have a role in the selection of antitussives for prescription. A good knowledge of the pharmacokinetics, dosage, efficacy, and side effects of the available antitussives provides for better management.