The company hasn’t made any changes at all to the actual chemical composition of the pill. But if the FDA agrees this is a significant change, generic drug manufacturers would have to postpone their own releases of the drug until they’ve undergone similar makeovers.

No one is suggesting that generics don’t have a place in the health care system. But especially when it comes to cardiology and neurology, doctors are becoming more skeptical that generics can automatically be assumed to be a perfect equivalent for name brand drugs — or even other generics for the same drug.

Blood levels and bioequivalence

While all generics must have the same active ingredients at the same strength, they are only required to provide very close blood levels. Some practitioners think slight variations in how dosages metabolize could cause side effects or other difficulties — particularly in cardiology and neurology where patients tend to be sensitive to even very slight changes in dosages.

To test the theory, one consumer group ran tests on Wellbutrin XL and its generic version, Budeprion XL 300. According to the tests, the two drugs did have different diffusion rates for the active ingredient, which could cause decreased effectiveness of the generic in some patients who switched to it from the brand name.

At particular risk of side effects or complications are patients who start taking one brand name or generic drug, and then switch to another. That’s especially true since patients on generics may not be informed when their pharmacist substitutes one generic for another.

Regardless, the FDA and the AMA both stand by generic medications and say the varying diffusion rates are still well within the standards set to maintain effectiveness of the drugs.

One thing is clear: More research is needed to figure out exactly how varying diffusion rates could effect a patient’s treatment. In the meantime, it’s probably worth it to explain to patients that while generics work and are safe, they shouldn’t ignore it if they do start to have side effects when switching prescriptions (or even after starting a new refill.)

If you’ve had experiences with patients having bad reactions to generics, share them in the comments.

While prices for almost all other goods have been dropping steadily — including generic medications which are down an average of 9% — costs for name brand drugs under patent protection are rising at rate not seen in years.

Critics say that the drug companies are trying to maximize profits now to make up for anticipated costs after health reform legislation passes. The final law is expected to include a provision that drug companies will give back up to $80 billion over the next 10 years in rebates to older Americans and government agencies.

The current increase in prices offsets the first year’s cost to drug makers.

For their part, drug makers say the price increases aren’t tied in any way to the expected health reform bills and are based solely on other market factors.

See the New York Times for more on this story.