I looked at a post by Dr Diana,
where she says
“I think it is entirely possible that Diamox may not agree with folks who can’t handle the overload of sulphur. Concerning sulphur allergies, I DO hear that most folks do fine with Diamox, even with a sulphur allergy, but obviously, you and your doctors will want to be careful with that, certainly. Some doctors (usually allergists) can put you through a desensitization program so that you can tolerate most anything. I think that may be important, because we don’t really have a non-sulphur alternative to lower our intracranial pressure, dad gum it.”
Although I personally am not aware of having any sulphur problem, my dosage of Diamox started low, then I built it up and it made a big difference to head and eye pressure problems. It might be worth you starting low, testing the water so to speak.
The Zantac, I take 2 tablets daily, one in a morning and one at night but I’m currently trying to wean these down, as I get the impression that it’s not wise to be on them long term.
The Cetirizine (Zyrtec) again I started low (under the supervision of an immunologist) and worked my way up. I’m now taking 3 of these a day, spaced out evenly over the day.