The FDA applies a rigid rule of what they call bioequivalence trying to make sure that generic medications are identical medicine with equal effects as the original one. When measured in the laboratory and in the simple, small trials with humans, a generic drug must deliver similar active component in the blood of patient virtually similar amount to almost the same proportion as the original medication.

The Food and Drug Administration supposes bioequivalence a substitute for therapeutic equivalency - the equal capacity of two formulations of drugs to cure disease or relieve symptoms. Doctors and pharmacists say that some drugs imitation, demonstrating bioequivalence with the source drug is not sufficient proof that similar drug will produce similar results.

There are a number of possible gaps in the rules of the FDA comparison, specialists say:

1. The FDA tolerance for the difference in the capacity, the release of an active component of the drug, the complex of healing, can be too wide.

2. The agency does not require realistic different formulations of the tests in big group of patients.

3. The FDA might be mistaken by the measurement of a generic medication in the capability to deliver the medication mixture to the blood. Most of the drugs act, in the organs, cell, tissues, not in the bloodstream.

Though the formula of brand-name and generic drug is the same, they could differ in some details. Although the two amounts equal share similar active component, usually look different. These differences can lead to minor variations in the way they act in people.

A branded drugs and their generic equivalent in almost any cases are devised with different dyes, fill materials and binding. Despite all these should come from list of pharmaceutical components approved by FDA, which are, in almost any cases, set up differently in each producer's product. A version of a medication may use sugar or lactose as an inactive component, other may not. However incidental components such as those can affect the method patients metabolize a drug and dissolve the active component ? slower or faster. And that may lead to variations in the 2 structures of the effects.

In general, the FDA allows a generic medication to release the eighty and one hundred and twenty five of the active component into the blood, compared with freedom in a single draught of medication original. Range that would be impractical different in the sense that most of the drugs are. Generic manufacturers and the FDA are defending the permissible range of variability as it is permitted between "lots" of the brand.

However, doctors and specialists in pharmacology notify that the FDA range could be too wide for some meds, especially if a medication has a "narrow therapeutic index" thin line between a dose that is ineffective or dangerous.

The variation in the rate at which a brand and generic release his freedom of active component could court tragedy with some meds, too. From this point of view, the experts said that "the formulas extended release" - the doses no more than once a day usually - can place specific problems.

If released formulating its therapeutic agent over twenty hours and other released a large percent in the first 5 hours and too little in the past 5, a patient can have a toxic density of the drug in the morning and gimp along with a dosage dangerously ineffective at the end of the day. In laboratory tests, and in small samples of human subjects, the FDA measures release rates at regular intervals. Pharmacologist, but warn that the intervals might not always be sufficiently fine.

Borgheini reviewed medical lit documenting differences in the effects of psychoactive drugs generic and branded twin. In the case of 3 anti-seizure drugs - valproic acid, phenytoin, carabamazepine (marketed under the trade name Tegretol, Cerebyx, Felbatol), the study found that generic preparations or not to release the correct dosage to patients or blood happened in higher paces of "breakthrough seizures."

Eventually, the agency requires not a lot of clinical evidence that generic drugs from a proposed work will be similar as the first drug in a wide cross slice of real patients. The FDA carries out quality control on the samples periodically generic post-marketing begins, and doctors and patients can provide issues with a generic medication to the contrary event monitoring system of the FDA. However neither manufacturers of generic drugs, nor does the FDA post-market studies that could indicate the patients are reacting to a different way that the generic brand counterparts

.

In the approval process for generic drugs, the FDA usually requires a producer to administer a single dosage of their proposed production to a group of twenty four to forty eight healthy volunteers and then shows blood levels of them periodically to measure the concentrations of substance active. The generic performance is compared then to the first drug in the same category.

However it may be not a good indicator of how big populations of ill patients will permit or respond to an alternative medication that has already been, approval process critics say.