Have you tried Prilosec, it's really the mildest of all the PPI's and least expensive I think.
But if you have to take ranitidine, the usual dose is 150 -300 mg a day according to my PILL BOOK, the official guide to medications. Some people have taken up to 600 mg with no side effects. It is most effective 1 - 3 hours after taking it. It says it is partly broken down by the liver and passes out through the kidneys. Occasionally, hepatitis or liver abnormality may occur. To find out more about it, go to drugstore.com or one of the medical sites and type it in and you will see all the side effects and drug interactions. I can tell you though, that I experienced alot of tiredness and mushy brain with ranitidine. It works good but I always felt a little out of it and some very mild depression. Just not real spunky. But give it a try and see what happens, we're all different in out reactions.
It seems that if all your symptoms are caused by Gerd that they should go away if you take ranitidine. Did they go away when you took the Nexium. Was it your insurance co. that won't pay for nexium anymore? Mine was just the opposite. I was taking Prevacid and they made me switch to Nexium. Maybe they will cover another kind of PPI if they work for you.
Hope this helps a little...good luck.