ask your pharmacist

What's the difference between brand-name drugs and generics?

Are generic drugs safe?
In almost all cases, generics work as well as their brand-name siblings, and often cost considerably less. This is possible not because of lower quality, but because research and advertising costs are much less for generics. Many insurance plans encourage you to accept the generic version of a drug whenever it's medically safe. Most states let pharmacists substitute a generic whenever your doctor approves it. The Food and Drug Administration (FDA) requires that generics be "bioequivalent" to their brand-name counterparts in order to get an "A" or top rating. This means the body can absorb generics as much and as fast as brand-name drugs. Some pharmacies, including drugstore.com, sell only "A"-rated generics.

When shouldn't generics be substituted for brand-name drugs?
Very few drugs have a "narrow therapeutic index," meaning that a small variation in dose can cause problems, such as too little effectiveness or too many side effects. With some drugs, including phenytoin (Dilantin), warfarin (Coumadin), and theophylline (Theo-Dur), you shouldn't switch from brand to generic—or vice versa—without your doctor's approval and close supervision. Always talk to your doctor, pharmacist, or both before asking for a substitute. They'll probably refer to the Food and Drug Administration's Approved Drug Products with Therapeutic Equivalence Evaluations, also known as "the orange book."

References:Law Notes. FDA position on product selection for "narrow therapeutic index" drugs, American Journal of Health-System Pharmacy 54 (1997).Levy G. "What are narrow therapeutic index drugs?" Clinical Pharmacology & Therapeutics May (1998).Mayo Clinic Family Health Book. William Morrow & Co., 1996.Merck Manual of Medical Information: Home Edition. Merck & Co., 1997.Yorke, J. "FDA Ensures Equivalence of Generic Drugs," FDA Consumer Special Report on New Drug Development in the United States Special Ed. January (1995). (You can read this article at www.fda.gov/fdac/special/newdrug/generic.html.)

This answer prepared 9/11/99.