What is one of the uses of codeine?

Codeine is primarily known for its role as a cough suppressant. It works by acting on the central nervous system to reduce the cough reflex, making it effective in treating persistent coughing that may occur from various conditions, particularly those associated with respiratory tract issues. This suppressant action is one of the key applications of codeine in medical practice, especially in formulations for cough syrups.

The other choices do not align with codeine's pharmacological properties: anesthetics generally refer to agents that induce a state of anesthesia; anti-inflammatory agents are used to reduce inflammation and pain; and antiviral medications are specific for treating viral infections. Codeine does not fall under these categories, solidifying its distinction as a cough suppressant.