Prilosec has, on their Web site, an interesting page on Medicare D and the well publicized coverage gap. They recommend the use of over-the-counter (OTC) drugs to avoid going into this financial gap.
"Avoid the COVERAGE GAP In Medicare Part D If you are enrolled in Medicare Part D, there is a phase of your coverage period when none of your prescription medication costs are paid for by your Medicare plan. This interval is called the Coverage Gap."
Prolosec OTC may have some information you haven't found elsewhere. What I like about it is the plain language. When it comes to Medicare D, be sure to double check everything. The government site mymedicare.gov is a good place to look for more resources.