what is good for post nasal drip that causes a scratchy throat?

Most any decongestant will do. I like Claritin-D.

A decongestant may or may not help. Not everyone gets relief using the same med or same combination of meds. Claritin-D isn't a decongestant, it's an antihistamine that contains a decongestant. A med that is strictly a decongestant is pseudoephedrine (Sudafed). Post nasal drip, PND, is a condition that often results from having allergic rhinitis. Nasal irrigation can prevent PND, using a nasal spray along with an antihistamine and decongestant, may help. Just try different combinations and see what works best for you.

thank you. i will definitely try it