The FDA standards for generics are 80% to 125% of AUC and Cmax (measures of bioavailability).  So you could be getting up to 20% less or 25% more drug with a generic than the brand.  Sometimes that matters, sometimes it doesn&#x27;t.<p>A great example of a generic drug problem is with Wellbutrin, used for smoking cessation and as an anti-depressant.  The FDA allowed Teva to market their 300 mg pill without actual bio-equivalence testing (they just extrapolated from the lower dose) and as a result a lot of patients had bad side-effects.  Teva recalled the product.[1]<p>[1]<a href="http:&#x2F;&#x2F;www.webmd.com&#x2F;depression&#x2F;news&#x2F;20121005&#x2F;teva-high-dose-generic-wellbutrin-xl-withdrawn" rel="nofollow">http:&#x2F;&#x2F;www.webmd.com&#x2F;depression&#x2F;news&#x2F;20121005&#x2F;teva-high-dose...</a>