Zyrtec may be less effective than Zyrtec-D at relieving nasal congestion. Individuals with certain medical conditions, such as high blood pressure or heart disease, may need to avoid medications ...

Claritin-D, Allegra-D, and Zyrtec-D all contain a decongestant called pseudoephedrine, the same active ingredient that powers Sudafed. It makes your nose feel less stopped up by narrowing the ...