Generic drugs in the U.S. are often introduced when the patent on a brand-name drug expires. That can mean huge savings for consumers, as generics usually cost a fraction of brand drugs.

Heidi Mitchell of The Wall Street Journal Health explains…

Stephen Schondelmeyer, a professor of pharmaceutical economics at the University of Minnesota College of Pharmacy, explains when to be cautious about switching to generics even though they usually have the same chemical effect on the body as brand-name drugs.

More doctors will write prescriptions for the generic version of a drug because it is much cheaper for the patient. And even when a brand-name drug is prescribed, some insurers will only cover the cost of the generic unless the prescription indicates the brand name is medically necessary.

The Food and Drug Administration evaluates generic drugs to make sure they are “the exact therapeutic equivalent of the originator brand-name drug,” Dr. Schondelmeyer says.

If the generic is an exact equivalent, it receives an A rating. He has never seen a documented case of an FDA-approved, A-rated generic that harmed a patient. “You’ll find anecdotal evidence, but usually the drug had a different absorption rate because the patient ate a big meal before taking the medication, or something of that nature,” he says.

If the generic doesn’t have the exact bioavailability profile – meaning that the drug is absorbed at a faster or slower pace into the bloodstream – then it will be B rated, he says. “B rated is not bad, it’s just a little different,” Dr. Schondelmeyer says. Occasionally the FDA will revise an A-rated drug to a B rating, as with the ADHD medication Concerta last November. A doctor probably won’t know a generic’s rating, but a pharmacist will, he says.

Dr. Schondelmeyer suggests that patients ask the first time they fill a certain prescription whether it is the A-rated generic equivalent. It will be 99% of the time. “If it’s B rated, you could ask the pharmacist to check with your doctor to see if it’s ok,” he says. “Usually, even with the B rated it will be fine.”

Patients sometimes think that generics are too slow or have different side effects than brand-name drugs, but there is no evidence of that, Dr. Schondelmeyer says. Patients taking a new medicine shouldn’t be concerned, he says.

“The FDA standard for comparing a generic to the originator brand allows no more difference than the same brand manufacturer would have between one batch of the brand and another batch of the same brand,” he says.

But, when switching from brand to generics, patients might notice a difference, the pharmaceutical economist says, though typically the body will adjust to the generic with ease. With certain diseases, like asthma or epilepsy, “because the risk of a problem like a side effect or strength being too low is serious, you may want to talk with your doctor or pharmacist before switching to a generic,” he says.

A difference between generic and brand name drugs is the binders, fillers and dyes. There are ingredients such as Xanthan gum used to hold pills together or dye to alter their color. Some patients can have adverse reactions to certain binders and dyes, and might react when switching to a generic, Dr. Schondelmeyer says. However, he says, “maybe less than a tenth of a percent” of people have a true allergy.

When a brand goes off-patent, the company may withdraw the original from the marketplace and introduce the same drug in a different format. A tablet becomes a capsule, for example. “Tablets and capsules have different dosages or bioavailability profiles, so you cannot substitute one for the other,” Dr. Schondelmeyer says.

wsjhealth.com
March 23, 2015

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