Schizophrenia Drugs: Is Newer Better?
Study Shows New Drugs Have Similar Side Effects, but Expert Disagrees
May 8, 2003 -- Newer schizophrenia drugs reported to cause fewer side effects may not live up to their reputation, suggests a new study. Researchers say they found little difference in nerve problems between newer and older schizophrenia drugs -- but not everyone agrees. The study does show the new drugs to be somewhat more effective.
In reviewing 31 previously published studies, researchers say they noted little difference between new and old schizophrenia drugs in preventing problems such as restlessness, muscle rigidity, cramps, and tremors.
Only one of nine schizophrenia drugs in this new class -- Clozaril -- was found by German researchers to produce fewer of these side effects. Still, they say that all of the newer schizophrenia drugs evaluated were moderately more effective than the four older medications evaluated. These newer schizophrenia drugs also included Risperdal, Seroquel, Solian, Zoleptil, and Zyprexa, as well as remoxipride, a drug not used in the U.S.
All have been used worldwide since the 1990s, when the first, Clozaril, got FDA approval. Though some cause weight gain and may require close monitoring of blood sugar, cholesterol levels, and white cell counts, the newer schizophrenia drugs are generally believed to prevent these nerve side effects commonly associated with the older drugs -- most likely by better maintaining the balance of two brain chemicals, serotonin and dopamine. Older medications employed since the 1950s only affect dopamine.
The new study, published in the May 10 issue of The Lancet, is a review of previous trials involving 2,320 patients -- usually a head-to-head comparison of drugs in both classes.
Lead researcher Stefan Leucht, MD, of the Hospital and Health Center for Psychiatry and Psychotherapy at the Technical University of Munich, and colleagues say much of the earlier research compared newer schizophrenia drugs to high doses of the older drug Haldol. This, they say, may have biased the results to suggest that the newer schizophrenia drugs have fewer nerve side effects.
If the current findings are confirmed by future studies, the researchers say this would be a good argument for the use of appropriate doses of older schizophrenia drugs since new generation drugs are much more expensive.
But another researcher says the newer schizophrenia drugs are more effective at preventing these Parkinson's-like nerve and muscle problems -- called extrapyramidal side effects. And they provide other advantages over older schizophrenia drugs such as Haldol and Thorazine in treating the disease, which affects about 2 million Americans. Symptoms of schizophrenia include hearing voices not heard by others, or believing that other people are reading their minds, controlling their thoughts, or plotting to harm them.
"The newer drugs haven't blown the older drugs out of the water in terms of symptom control. However, they are more effective at preventing relapse, and patients seem more willing to stay on their treatment with them compared to the older drugs," says Jeffrey A. Lieberman, MD, director of the Mental Health Clinical Research Center at the University of North Carolina School of Medicine. "And the newer drugs are better at controlling symptoms such as depression."