Topical decongestant
Topical decongestants are decongestants applied directly to the nasal cavity. Their effectiveness by themselves in the common cold appears to have a small benefit in adults. Topical decongestants should only be used by patients for a maximum of 5–7 days in a row, because rebound congestion may occur in the form of rhinitis medicamentosa. When used in adults for a short period of time side effects appear to be few. Mechanism of action. Topical decongestants are vasoconstrictors, and work by constricting the blood vessels within the nasal cavity.