Generic form of Imitrex?

I have been taking Imitrex for my migraines for many years. By now, you usually see a generic form of a drug come out. At a little over $200 US for 9 stinkin' pills is outrageous, but it works so I pay it - out of pocket no less. This drug works great for me, but I'm at the point, with the current economy, that I won't be able to pay for it and will have to try something else.

What are the rules for allowing other manufacturers to make a generic of a name brand drug. It didn't take long for Claritin and Prilosec to come out OTC. A bunch of other migraine meds have generics. Just over the past year my prescription has gone from $118 to over $200 for the 9 pill pack. I don' t have to take them but every few months if I'm lucky but its to the point that I will suffer a few days first before resorting to taking one of my "gold" pills.

Now there's the Imitrex/Naproxen pill on the market, I can imagine what THAT one costs! If they're muddying up the recipe, shouldn't we who take the regular imitrex get a break on the price or at least be offered a generic?

My pharmasist said that drugs are allowed to hold the patent for 5 years. I know its been at least that long. I think the hike in price is the greedy drug manufacturer getting every last bit of coin before they have to release the patent.