What are Trade-Name and Generic Drugs?

It is important to know that drugs often have several names. When a drug is approved by a government agency, such as Food and Drug Administration (FDA) in the United States, it is given a generic (official) name and a trade (proprietary or brand) name. The trade-name is developed by the company requesting approval for the drug and identifies it as the exclusive property of that company. For example, minocin is the trade-name and minocycline is a generic name for the same drug.

In practice, when a drug is under patent protection, the company will market it under its trade-name. However, when the drug is off-patent (no longer protected by patent), the company may market its product under either the generic name or trade-name. Other companies that file for approval to market the off-patent drug must use the same generic name but they have the option to create their own trade-name (but not the trade-name used by the original patent-holder). As a result, the same generic drug may be sold under either the generic name or one of many trade-names.

In general, the generic version of the off-patent drug is usually at a lower price than the original trade-name drug as the generic manufacturer does not have to recover the original costs of drug development and usually spends much less on marketing, nevertheless, the drug has to be approved by the concerned government agency before introducing to the consumers.

Can generic drugs interchangeable with their trade-name counterparts? And are they as effective as the original version?

When a company develops a generic version of a trade-name drug, they must figure out how to make their version to be bioequivalent to the original drug, i.e. that the generic version releases its active ingredient (the drug) into the bloodstream at virtually the same speed and in virtually the same amounts as the original drug.

The concerned government agency, such as FDA will approve a generic drug if their studies indicate that the original trade-name drug and the generic version are essentially bioequivalent. In this respect, they need to make sure that a new generic drug contains the appropriate amount of the active (drug) ingredient, and that it is manufactured according to federal standards (Good Manufacturing Practices). In addition, the generic version needs to be differed from its trade-name counterpart in size, color, and shape.

Theoretically, any generic drug that is bioequivalent to its trade-name counterpart may be interchanged with it. In order to limit costs, many doctors write prescriptions for generic drugs whenever possible. Even if the doctor has prescribed a trade-name drug, the pharmacist may dispense a generic drug unless the doctor wrote on the prescription that no substitution can be made.

We may want to know that sometimes generic substitution may not be appropriate. For example, in cases in which small differences in the amount of drug in the bloodstream can make a very large difference in the drug's effectiveness, in this case, generic drugs are often not substituted for trade-name drugs, although bioequivalent generic products are available. Warfarin (trade-name: coumadin), an anticoagulant, and phenytoin (trade-name: dilantin), an anticonvulsant, are examples of such drugs. Another thing is that, a generic version may not be appropriate if it contains an inactive ingredient that the person is allergic to.

To sum thing up, drugs that must be given in very precise amounts are less likely to be interchangeable, because the difference between an effective dose and a harmful or an ineffective dose (i.e. the margin of safety) is small.