Prescription drugs can be grouped into two main classes: brand names and generics. To gain governmental approval, in the United States and elsewhere, these latter generic versions must meet a standard of therapeutic equivalence. This requires the manufacturer to prove its drug is bioequivalent, with the same active ingredients, efficacy and side effects.
Most countries oversee their own medical and pharmaceutical industries, making sure doctors are prescribing drugs that have been proven safe and effective. In the United States, the Food and Drug Administration (FDA) handles this task. For 2010, the agency approved 21 new presription drugs, slightly down from previous years. Some are new, brand-name drugs; others are generics with therapeutic equivalence, attempting to make often-expensive, brand-name medications more affordable for the average patient.
Therapeutic equivalence is established by meeting certain criteria. This involves determining if the new alternative has the same active ingredients, potency and performance. Other important considerations are whether the generic is administered and if the body responds in the same way as the brand-name product. These drugs have the same requirements for labeling, chemistry inspections and testing periods as do brand-name drugs, but establishing bioequivalence eliminates the more stringent brand-name requirements for animal and clinical research — at least in the United States. To establish this, government chemists compare the model brand name to the generic to judge whether both have the same chemical composition, absorbency and blood concentration over time.
Some drugs have therapeutic equivalence with a handful of other approved drugs. The most common model, however, is a brand-name and generic pairing. According to the FDA's Center for Drug Evaluation and Research, drug companies have 17 years of patent protection for their brand-name products, then a competitor can attempt a generic knock-off. After a company applies for FDA approval, four separate reviews must be passed before a drug can be marketed and sold. The manufacturer's facility is inspected, the product's labeling is checked for accuracy, the drug's bioequivalence is established, and the chemical composition is examined to see if it is not equivalent.
Since generics are often made by competing drug companies, the new formulations are occasionally suspected of having different qualities than the brand-name medications, despite the governmental approval. Occasionally, controversy is sparked. In just the first six months of 2007, for example, the FDA was informed of 85 patients who reported a diminishing of effect when they switched from the brand-name depressant Wellbutrin® to the alternative bupropion, despite the therapeutic equivalence. After further study, however, the agency concluded that the reports were apparently an anomaly.