drug antitussive cough suppressants cough suppressant An agent that suppresses cough. Antitussives have a central or a peripheral action on the cough reflex, or a combination of both. Compare with expectorants, which are considered to increase the volume of secretions in the respiratory tract, so facilitating their removal by ciliary action and coughing, and mucolytics, which decrease the viscosity of mucus, facilitating its removal by ciliary action and expectoration. CHEBI:51177 anti-tussive chebi_ontology