When it comes to medicine, brand names aren't always best. According to the Food and Drug Administration, generic drugs are just as safe and effective as their brand-name counterparts. In fact, the law requires it. By FDA regulations, any generic drug has to have the same active ingredients in the same amounts as its brand-name counterpart. Generic drugs must also be bioequivalent to brand-name drugs, meaning that the drug has to be absorbed into the blood at a rate within 20 percent of that for the brand-name drug.

Still, doctors sometimes prefer to prescribe brand-name drugs, especially if the exact dosage is critical. Certain drugs -- including the blood thinner warfarin (brand name Coumadin) -- require patients to maintain a constant and precise level of medication in the blood over long periods of time. In physician speak, these drugs are said to have a narrow therapeutic index (NTI). Some doctors are hesitant to replace NTI drugs with generics for fear of upsetting a delicate balance. If they do make the switch to generic, they generally run extra tests to make sure the drug is working properly.

In contrast to the lengthy testing a new drug undergoes, the approval process to market generics is usually limited to bioequivalence data from the laboratory, and the results of a trial with a few dozen healthy volunteers.

The FDA also regularly inspects the facilities that produce generic drugs. These facilities must meet the same standards as the factories that produce brand name drugs.

No, there are some differences. The Food and Drug Administration grades generic drugs for bioequivalence, and publishes that information in a compendium commonly referred to as the Orange Book. A small proportion of generic drugs (4 percent) are rated as "non-therapeutically equivalent," and a handful of those are considered "non-equivalent." If you're interested in looking up the generics you use and discussing that information with your doctor, the Orange Book is available online on the FDA's Web site.

It should be noted that a few older generic drugs have never been tested for bioequivalence. The FDA didn't start monitoring the safety of new drugs until 1938, and some generic drugs introduced before then were simply "grandfathered." The heart medication digoxin (brand name Lanoxin) is a prominent example. Doctors have no way of knowing if a particular dose of digoxin will be more powerful or less powerful than a dose of Lanoxin. In fact, the authors of a report in a 2001 issue of the Southern Medical Journal warn that substituting generic digoxin for Lanoxin "is not advised."

If you're currently taking a brand-name drug or if your doctor suggests a new prescription, ask if there's a generic alternative. The switch could save you hundreds of dollars a year. (For more on cost savings of generics, see Saving Money on Drugs.) If you're taking a drug with a narrow therapeutic index, don't be surprised if your doctor balks at making a switch, especially if the drug is working well for you. If your doctor doesn't want to switch to generics for medical reasons, make sure that the "no substitutions" box on your prescription is checked and the pharmacist fills the prescription exactly as written.

No matter what drug your doctor prescribes, be sure to read the label carefully and follow the instructions to the letter. Whether it's a brand name or a generic, a medication is only safe and effective when taken as directed.

-- Chris Woolston, M.S., is a health and medical writer with a master's degree in biology. He is a contributing editor at Consumer Health Interactive, and was the staff writer at Hippocrates, a magazine for physicians. His reporting on occupational health earned him an award from the Northern California Society of Professional Journalists.

References

First published July 8, 2003
Last updated November 14, 2007
Copyright © 2003 Consumer Health Interactive

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