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.
“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.”