E.B.
A couple of questions: have you spoken with the pharmacist who dispenses his prescription medications? That is your best source for medicine advice. My daughter takes lots of meds, and I always ask to consult with the pharmacist (with my daughter's chart pulled up) when purchasing an over-the-counter thing.
My second question is you said he had allergy testing and was negative to everything, but is prone to outdoor allergies when he gets a cold. Can you elaborate on that? And what kind of allergy testing did he have? Did he have the blood test, the skin prick test?