Is it possible that taking prednisone(sp) and zpac make you have a dry mouth?

Unlikely: The two medications that you mentioned do not typically cause a dry mouth. You did not mention why you are taking those medications. It is more likely that something else is the cause of your dry mouth, although I have learned over the years that nothing is impossible and you may be having an atypical side effect. I would recommend that you discuss this issue with your treating physician.

Prednisone and Z-Pak: Along with its wanted effects, a medicine may cause some unwanted effects. The most common side effects of the prednisone and Z-Pak are diarrhea, nausea and dry mouth. These side effects may go away during treatment as your body adjusts to the medicine.