What is the main function of an antitussive?

The main function of an antitussive is to suppress coughing. Antitussives work by acting on the cough center in the brain or by soothing the irritated throat and airways, which helps to reduce the urge to cough. These medications are particularly useful in situations where a cough is dry and nonproductive, allowing individuals to find relief from the discomfort associated with frequent coughing.

While other options pertain to different therapeutic effects, they do not relate to the primary action of antitussives. Pain relief is associated with analgesics, inflammation reduction is the domain of anti-inflammatories, and allergy alleviation is typically addressed with antihistamines. Therefore, the focus of antitussives is specifically on the suppression of cough, making this choice the correct answer.