And, only aripiprazole and ziprasidone among the second-generation drugs did not induce more weight gain than the first-generation drug haloperidol (Haldol), the study found.
Comparing first- and second-generation drugs, Davis's team also found that second-generation drugs produced fewer "extra-pyramidal" side effects such as unintentional muscle contractions, Parkinson-like symptoms and restlessness than Haldol.
However, only a few of these second-generation drugs reduced these side effects compared with low-dose Haldol, the researchers noted.
In addition to Haldol, other first generation antipsychotics include chlorpromazine (Thorazine), fluphenazine (Prolixin), mesoridazine (Serentil), perphenazine (Trilafon), and trifluoperazine (Stelazine), according to the U.S. National Institute of Mental Health.
Davis thinks that classifying these drugs as first- or second-generation should be abandoned. "For patients, there is a choice only some drugs are efficacious, only some drugs cause obesity, and only some cause tremor. The doctor should choose based on whether he wants to go for efficacy, primarily, or wants to avoid side effects and the patient's history," he said. "It's a value judgment about which one should be used."
Dr. Peter Tyrer, who's with the Department of Psychological Medicine at Imperial College London in England, and co-wrote an accompanying editorial in the journal, thinks these drugs should be evaluated on their own merit and not as part of a group of newer or older drugs.
"We should dump the labels of first- and second-generation in our descriptions of these drugs," he said. "They have been used primarily as a marketing ploy to convey the impression of a steady improvement in the benefit-risk ratio of these agents, an impression that has been exposed as completely inaccurate."
Dr. Thomas R. Insel, director of the U.S. National Institute of Mental Hea
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