What's the difference between benadryl (diphenhydramine) and sudafed?

Medical questions: Benadryl (diphenhydramine) is an antihistamine, good for allergies and to lessen the drainage during an upper respiratory infection. Sudafed is a decongestant, good for helping you breath through a stuffy nose from a cold, bad allergies or sinus problems. Sudafed can also raise blood pressure, and shouldn't be taken on a regular basis.