Generic Drugs--Just as Good as Brand Names?

The next time you need a prescription filled, there’s a 40% chance of getting a generic drug instead of a brand-name medicine.

And by the year 2000, the chances will increase to 50-50, according to forecasts from the Washington, D.C.-based Generic Pharmaceutical Industry Assn.

What’s fueling the boom? Cost savings of 50% or more, patent expirations on brand-name drugs and health insurers’ emphasis on cost containment.

But are generic medicines as good as the original brand-name version? Usually, but not always.

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The Process: So how is it that you end up with a brand name instead of a generic or vice versa?

A physician may write a prescription for a brand-name medicine, but if he or she has not issued a “do not substitute” order, a pharmacist may substitute generic, unless state regulations forbid it.

Some states have a “negative formulary system,” permitting pharmacists to select equivalent drugs in all categories except those listed. California dropped its negative formulary system a few years ago, says Scott Lewis, spokesman for the California Department of Health Services.

States with a positive formulary system usually adopt the FDA’s Orange Book, which lists drugs that are interchangeable.

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The Exceptions: There are two instances in which most pharmacists would hesitate to use generic drugs, says Benjamin F. Banahan III, an investigator at the Research Institute of Pharmaceutical Sciences at the University of Mississippi. Pharmacists might avoid using generics from a company with a history of problems.

“There are some small generic manufacturers who have had some problems in the past in terms of abiding by all the [government] regulations,” he says. (But these days, many major manufacturers are also producing generic versions of their own name-brand drugs.)

Pharmacists avoid generics to fill prescriptions for what they term “critical-dose” drugs--medicines for which the difference between an effective dose and an ineffective (or even toxic) dose is very slight.

“The effectiveness of any drug depends on how much of it is available to the body through the bloodstream,” Banahan says. But this availability is even more crucial with certain drugs.

Historically, several types of drugs have been considered critical-dose, says Mitch Rothholz, a pharmacist at the American Pharmaceutical Assn. Among them: digitalis glycosides (for heart problems), warfarin anticoagulants, theophylline (for asthma), thyroid preparations, estrogens, anti-arrhythmic medicines and anti-epileptic drugs.

Generic manufacturers must prove that their drugs are equivalent to the pioneer drug--absorbed by the body at the same rate and to the same extent--to get Food and Drug Administration approval. Many critical-dose drugs aren’t available in generic versions, Banahan says, simply because none has been approved.

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The Survey: In a recent survey, Banahan presented a list of 15 prescription drugs to 1,290 hospital and retail pharmacists, asking their comfort level in substituting generics for brand-name drugs.

Pharmacists were most uncomfortable substituting generics for three drugs: Coumadin, an anticoagulant; Lanoxin, a heart drug, and Dilantin, an anti-epileptic.

Generic versions of Lanoxin and Dilantin are on the market, a representative for the manufacturer says, but not for Coumadin. A generic for Coumadin, available a few years ago, was taken off the market because of therapeutic problems, Banahan says.

Banahan’s study, presented at a recent meeting of the American Assn. of Pharmaceutical Scientists, was funded by Dupont Pharma, the manufacturer of Coumadin, which wanted to know whether pharmacists viewed its drug as a critical-dose medicine.

Pharmacists said they would have much less concern about substituting generics for several other drugs, Banahan says, including Lasix, a diuretic; Xanax, a tranquilizer; Ceclor, an antibiotic; Tagamet, an anti-ulcer drug, and Naprosyn, an anti-inflammatory.

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The Caveats: Caution is the rule, Banahan says, whenever a prescription medicine is switched--whether the change is brand to brand, brand to generic, generic to brand or even generic to generic.

It’s not uncommon to have three or four manufacturers for a single generic drug, Banahan says. “They’re not going to come out identical in terms of how [much of the drug is absorbed] into the body.”

In many cases, though, the differences aren’t noticeable in terms of effectiveness. He suggests asking if it will be possible to obtain the drug from the same manufacturer if you expect to be on a long-term medication.

* Doheny cannot answer mail personally but will attempt to respond in this column to questions of general interest. Please do not telephone. Write to Pharm Report, Life & Style, Times Mirror Square, Los Angeles, Calif. 90053.