Sudafed blocked nose spray with xylometazoline hydrochloride works in minutes to help clear blocked noses and relieve sinus pressure caused by colds and hayfever the metered spray gives an exact dose that lasts for up to 10 hoursas an alternative doctors can also prescribe medication that can assist with flu please visit our online doctor service to proceed with an influenza consultation our uk registered gp will review your details and if appropriate can provide a prescription for the mai