That said, it is not at all rare for patients who switch to a generic from a brand-name medication to experience a difference. Sometimes they feel a return of the old sadness, anxiety, and helplessness that the antidepressant helped to lift. Other times, they get an unusual jolt of the same side effects that hit when they began taking the first drug.
There’s not been a “systematic problem” with generic antidepressants, says Jonathan Edward Alpert, MD, PhD, chief of clinical psychiatry at Massachusetts General Hospital in Boston.
“In general,” he says, “they’ve been very good. But doctors need to be vigilant.”
Differing Responses to Generic Antidepressants
There are scattered reports of people experiencing a return of depression symptoms -- or side effects -- when they go on generics.
In one recent study, a group of Canadian psychiatrists described seven cases in which patients with depression were taking Paxil or Celexa. When their medication was switched to the generics -- paroxetine and citalopram – they experienced a relapse of their depression. Other people with depression have reported a recurrence of side effects when they switched to generics, and one report showed that switching from one generic to another can also result in a relapse.
The Difference Between Generic and Brand-Name Antidepressants
Usually it isn’t that the generics are inferior to the brand name drugs. But generics may be different in ways that are slight but have impact.
The FDA requires that generics provide blood levels of a drug that are 80% to 125% of what the brand name drug produces. However, the generic antidepressant may be formulated with different non-active ingredients -- the stuff that binds and coats the pills – which can affect the rate at which a drug is released. Also, generics aren’t generally tested in a wide variety of patients. So blood levels may vary more than the FDA-established limits in people with certain genetics or medical conditions.
With somewhat older antidepressants, such as fluoxetine (Prozac), several different manufacturers make the generic antidepressants, each using different non-active ingredients. Thus, each generic brand may have slightly different effects.
“In general, generics have been as effective as brand-name antidepressants. And they’re less expensive, so it makes sense to use them,” says Alpert “But,” he adds, “the differences for a given individual might be enough to throw off that individual’s response or to cause additional side effects.”
Making Adjustments With Generic Antidepressants
Gabrielle Melin, MD, a psychiatrist at the Mayo Clinic in Minnesota, agrees.
“In my experience it’s a minority, but if someone says, ‘I switched to generic citalopram and went downhill,’ I’m going to pay attention. I’ll consider other factors that may have brought back the symptoms. But if the patient can afford the brand name, we may switch back, or we may try some other medication. It depends on the patient.”
Sometimes, therapists say, it’s just a matter of adjusting the dose. The same patient who did well on 20 micrograms of Celexa might need, say, 30 or 40 milligrams of the generic citalopram to get the same effect.
So What’s the Bottom Line With Generic Antidepressants?
Psychiatrists have little data to work with when making decisions about the use of generics, largely because there is not a great deal of research on their use. The companies that make them have no interest in paying for dose-comparing clinical trials. Neither do the makers of the brand-name drugs that the generics replace, says Bradley Gaynes, MD, MPH, a psychiatrist and professor of psychiatry at the University of North Carolina, Chapel Hill.
“It’s the kind of thing that the National Institutes of Health might want to study, but they are usually interested in what’s the best new thing,” says Gaynes. “Pharmaceutical companies aren’t likely to fund a study unless they are confident their drug will do better.”
The bottom line is, in general, generic antidepressants are safe and effective. But as with any medicine, it’s important to keep track of how it affects you and discuss any concerns about it with your doctor.