People who are asked to switch from a brand name drug to a generic often wonder if the change will cause them any problems. Usually a person makes the transition to a generic drug without noticing any differences.
But not always. For example, several years ago, a patient of mine received a generic pill instead of the brand name antidepressant from the pharmacist. Over the next month or two, he felt slightly apathetic. A few poor-judgment calls caused him mild embarrassment. Apathy can occur when an antidepressant dose gets too high, but he worried that if he reduced the dose he'd risk a relapse of his depression. After weighing his options, he decided to switch back to the brand name drug and pay a higher copayment. He didn't suffer any lasting harm, although the treatment was more expensive.
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What's a "Generic" Drug?
Let's look at what it means to go from a brand name to a generic drug and what the possible pitfalls are.
People may think of a generic as a "knock-off" of the original — like the fake Rolex watch that a Manhattan street vendor might sell. But that comparison is not correct.
Every medicine has a generic name. Often it has a brand name, too. Chemists give drugs their generic name. The brand name is given by a drug company's marketing department.
Companies that develop a new drug hold a patent that entitles them, and only them, to sell it. This helps them recoup the tremendous costs of researching, testing and marketing a new product. If the product is successful, they also earn a healthy profit.
Once a patent expires, other drug companies can manufacturer and sell a medication made with the same active ingredient or chemical that is in the brand name drug. Since these companies have not put any money into research or marketing a generic drug, they can make and sell it much more cheaply.
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Brand and Generic Drugs: Are They Identical?
Generic pills, however, also contain inactive substances that are different from the brand name pill. (The U.S. government requires that the drug look different so it won't be mistaken for the original. This prevents fraud.)
Those inactive ingredients can cause subtle changes in how the active chemical is delivered to its target in the body. The drug may break up and dissolve in the gastrointestinal tract either faster or slower than the brand name drug. This can affect how quickly it gets absorbed into the blood stream.
Think of it this way: You want to "FedEx" a package. FedEx is a brand name. Other companies such as UPS or the U.S. Postal Service sell a generic version called "overnight delivery." The delivery speed is a bit faster or slower depending on which service you use. The costs will vary, too. Any of the options should get your package to its destination.
The U.S. Food and Drug Administration has rules about how close the generic version should be to the original:
- It should contain the same amount of active drug (often measured in milligrams).
- It must be taken by the same route (for example, by mouth).
- It should be "bioequivalent," meaning that it delivers about the same amount of drug into the bloodstream.
"About the same" means that generic pills may deliver, on average, slightly more or less of the drug into your bloodstream.
Thus, although the active ingredient in a generic drug is the same and it has the same effect when it reaches the brain or other body organs, the amount circulating in your blood at any given time could vary slightly. In most cases, the differences are not clinically significant and the person taking the drug notices no change at all. But occasionally there are signs that the dose needs to be adjusted — either there is a small reduction in effectiveness or a noticeable increase in adverse effects.
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Small Cost, Potentially Big Benefit
My mildly embarrassed patient who feared a relapse decided to stick with the brand name antidepressant — and I understood his position. He was not comfortable with the idea of experimenting with a lower dose of the generic drug, which might well have been just as effective for him.
A second patient, on the other hand, was taking a brand-name antidepressant until the patent on the drug expired. His pharmacist gave him the new generic version. Within weeks, he noticed an uncomfortable sensation of heat and flushing that would last a few minutes then go away. This sounded like it could be a side effect of the drug, resulting from a higher blood level. I asked him to adjust the dose downward, the uncomfortable feeling went away, and he continued to enjoy the positive effects of the antidepressant.
Depression is so prevalent that reducing the cost of medication is a boon to all of us. In most cases, changing to an equivalent low-cost generic from a high-cost brand goes smoothly. But it's also normal to be anxious about making this change.
Depending on the state in which you live, pharmacists may be required to give you the generic version of a medication unless your doctor indicates on the prescription that no substitution is allowed. It's typical for a generic version to be substituted for a brand-name drug when a drug's patent runs out. The pharmacist won't necessarily know that the switch has occurred, and the doctor won't either. This makes it all the more important for patients to pay attention to what they are getting and asking their doctor or pharmacist about it when they notice a change in the pill.
If the pharmacist dispenses a generic form of a drug to you, you probably won't notice any change it its effects, even if your blood level rises or falls slightly. But occasionally, a person may have a recurrence of symptoms or an increase in adverse effects. In most cases, the effects are minor and a small adjustment will put you back on your proper course.
Michael Craig Miller, M.D. is Editor in Chief of the Harvard Mental Health Letter. He is also associate physician at Beth Israel Deaconess Medical Center and assistant professor at Harvard Medical School. He has been practicing psychiatry for more than 25 years and teaches in the Harvard Longwood Psychiatry Residency Program.