Generic versions of several popular brand-name drugs are muscling their way onto the prescription shelves. Generic equivalents of Lexapro (escitalopram) used to treat depression and generalized anxiety disorder; Boniva (ibandronate) to prevent and treat osteoporosis; Plavix (clopidogrel) used to prevent strokes and heart attacks; and Avapro (irbesartan) used alone or in combination with other medications to treat high blood pressure, may appear soon with others to follow.
CDER’s Division of Drug Information responds to inquiries from consumers, health care professionals and the pharmaceutical industry about many drug related issues. Here are answers to the most frequently asked questions submitted to DDI about generic drugs.
When will the generic version of my medicine be available?
The availability of generic drug depends on many factors, including patent expiration and FDA approval of the generic drug application.
Each drug may hold several patents. The availability of generic versions depends on the court ruling of the validity of any pertinent patents and the expiration dates. FDA publishes the Orange Book. The Orange Book lists the patent number and expiration date of each patent that claims the drug or method of using the drug.
Each drug may have multiple patents, and not all patents are listed in the Orange Book. For example, drugs may have patents that are listed with the U.S. Patent and Trademark Office, but are not required to be listed in the Orange Book.
The availability of generic versions also depends on whether generic applications for approval are submitted to FDA, and whether these applications contain sufficient information for approval. If a generic drug product is ready for approval before the expiration of any patents, FDA issues a tentative approval letter to the applicant. A tentative approval does not allow the applicant to market the generic drug product.
FDA delays final approval of the generic drug product until all patent issues are resolved.
Can generic drugs contain different ingredients than their brand name counterparts?
Though generic drugs must contain the same active ingredients as their brand name counterparts, they may contain different inactive ingredients.
Do generic drugs have the exact same amount of active ingredient as their brand name counterparts?
All FDA-approved generic drugs must be equivalent to the innovator product. It is a common misconception that FDA allows generic drugs to vary from brand name products by as much as 45 percent. This is not the case.
Does FDA review generic drugs under the same process and brand name new drugs?
The FDA-approval processes for generic drugs and new drugs are different. The safety and effectiveness of innovator drug products have already been demonstrated by adequate and well controlled studies by the pioneer drug manufacturers. The generic firm must demonstrate through a bioequivalence study that their drug product delivers to the body the same amount of the active ingredient, at the same rate as the brand name counterpart.
Generic drug applications are termed “abbreviated" because they are generally not required to include animal and human test data to establish safety and effectiveness. Instead, generic applicants must scientifically demonstrate that their product performs in the same manner as the brand name drug.
To meet FDA approval, proposed generic drug products must:
- Have a previously approved drug which is the "same" as the proposed generic drug.
- Have the same active ingredient, route of administration, dosage form, and strength.
- Show that the generic product will produce similar activity or therapeutic results in a patient population as the brand name product.
- Have the same product characteristics as the brand name product.
- Contain labeling information that is virtually the same as that of a previously approved product.
- Have in the application documentation of the complete chemistry, manufacturing, and controls of the drug product, for each step of the manufacturing process starting from the synthesis of the raw material, through the packaging and labeling of the finished product.
- Assure that the raw materials used, as well as the finished dosage form, meet the specifications set forth in the United States Pharmacopoeia (USP), the official drug compendium of this country.
- Demonstrate, prior to approval, that the product is stable under extremes of temperature and humidity; after approval, continue to monitor the product under room temperature conditions.
- Provide a full description of all facilities used in the manufacture, processing, testing, packaging, labeling, and control of the drug product. All firms must certify that they are in compliance with regulations pertaining to current good manufacturing practices and facilities must be inspected by FDA.
Before CDER’s Office of Generic Drugs (OGD) approves a product, an FDA investigator will conduct a product-specific inspection to assure that the firm has actually followed the conditions set forth in the generic drug application, and audit data used to support the application.