Topical decongestants are decongestants applied directly to the nasal cavity. By applying them directly to the site of action, topical decongestants relieve nasal congestion while reducing the side effects associated with systemically-acting decongestants, such as high blood pressure. Topical decongestants should only be used by patients for a maximum of 3 days in a row, because rebound congestion may occur in the form of rhinitis medicamentosa. Topical decongestants are a common form of nasal relief, due to their quick effects which can clear the sinus in up to ten seconds.