Is dextromethorpan effective for treating a productive cough?

Dextromethorphan is primarily used as a cough suppressant for dry, non-productive coughs, rather than for productive coughs, which involve mucus or phlegm. It works by acting on the brain to reduce the cough reflex. For productive coughs, expectorants like guaifenesin are typically recommended to help thin and clear mucus. Therefore, dextromethorphan is not considered effective for treating productive coughs.