A study comparing medications for schizophrenia found two of three newer antipsychotic drugs are more effective in patients who did not benefit from an older medication, according to a research.
The study is one of the latest stemming from the longstanding Clinical Antipsychotic Trials for Intervention Effectiveness (CATIE). Dr. Scott Stroup, associate professor of psychiatry in the UNC School of Medicine, is the lead author.
In the original CATIE study, 257 patients were initially selected randomly to take the older antipsychotic drug perphenazine. Of these, 192 discontinued the medication for various reasons, including ineffectiveness and intolerable side effects. Among those who discontinued, 114 agreed to be randomly chosen to take one of three newer antipsychotic medications - olanzapine, quetiapine or risperidone.
In the current study, Stroup and colleagues compared the effectiveness of the medications by determining how long patients stayed on their assigned medication. Those taking quetiapine stayed on the longest — averaging about 10 months before stopping. Those taking olanzapine discontinued after an average of about seven months, and those taking risperidone discontinued after an average of four months.
Although the discontinuation results suggest that olanzapine was generally on par with quetiapine, patients taking olanzapine had more weight- and metabolic-related side effects than those on the other medications. While none of those patients taking quetiapine discontinued use due to weight gain or metabolic side effects, 13 percent of those assigned to olanzapine discontinued it due to weight gain or metabolic problems and 5 percent of those on risperidone did so.
"The results favor quetiapine and, to an extent, olanzapine," Stroup said. "These findings diverge somewhat from other CATIE studies in which second generation medications are compared, but overall there is consistency."
Olanzapine is good at addressing symptoms but weight gain is problematic. Risperidone is a good choice overall but was not well tolerated by those who stopped perphenazine, presumably because of similarities in the two drugs, Stroup said.
"Quetiapine may have worked particularly well in the people who stopped perphenazine because these two drugs are fairly different from each other," said Stroup. "These results remind us of the considerable variability in clinical circumstances and of our need to be responsive to an individual's needs and preferences."