Generics are supposed to have the same amount of ACTIVE ingredient, but the INERT components can vary. This may not seem important at first glance, but the inert ingredients can make a statistically significant difference in metabolism of active ingredient such as lagtime and rate of absorbtion and also percent bio-availability.
Also the allowable variance in active component(per FDA) seems to be as much as +/- 20% variance. If you start on a particular generic brand, best to stick to it as the next generic mfg. might have more or less than what you are currently on, up to about 40% active variability if you take the extremes possible into account.
While it is possible to achieve similar results with generics vs. patent, I would strongly advise against SWITCHING between generic brands or to patent if something is working for you, regardless of whether it is generic or patent. Who needs to go through the grief of titration yet again? Typically they all look a bit different or have differing imprints. Your pharmacy may also switch generic suppliers-just something to be aware of.
On the other hand, if you have recieved a generic that is not working for you after having tried dosage level changes, it might be worth trying the patent to see if there is any change in effect. It would at least afford you the ability to continue medication without going through the grief of tapering off one drug to try another. Just be aware of the possibility that you might find yourself over or under dosed when switching drug manufacturers.
I've heard that Ritalin (patented) is clearly effective for some people diagnosed with ADD while generic formulations of methylphenidate have caused exacerbated nasty side effects with marginal benefits for those same people.
One of the top rated endocrinologists in Los Angeles has signs posted in his waiting room that try to explain the variability of drug effectiveness from manufacturer to manufacturer. He discusses these variabilities when perscribing medication to avoid complications with perscriptions. I have tried to explain what he told me to the best of my ability.
Just remember, antidepressant drugs are not a cure, they can help provide relief (Excedrin for a headache) through a nasty patch, but will never be as effecti