Rapid-dissolving, sublingual asenapine is effective against both positive and negative symptoms of acute schizophrenia and is well tolerated in these patients, according to an article in the October issue of the Journal of Clinical Psychiatry.

Data had previously been presented at the American Psychiatric Association's annual meeting and at the annual congress of the European College of Neuropsychopharmacology.

In the six-week study, 174 patients with schizophrenia were randomized to asenapine 5 mg twice daily, risperidone 3 mg twice daily, or placebo for six weeks. Asenapine was more effective than placebo in reducing total Positive and Negative Syndrome Scale (PANSS) score as well as positive symptoms and negative symptoms when measured alone. Risperidone was more effective than placebo in reducing positive symptoms.

The majority of patients (83 percent asenapine, 79 percent placebo, 90 percent risperidone) experienced at least one adverse event during the study. Adverse events were generally mild to moderate in severity. The most commonly reported (greater than or equal to 10 percent of patients) were insomnia, somnolence, nausea, anxiety, and agitation in the asenapine group; insomnia, somnolence, anxiety, agitation, and headache in the risperidone group; and agitation, headache, anxiety and dizziness in the placebo group.

There was no difference between treatment groups on the incidence of extrapyramidal symptoms. Prolactin levels (greater than or equal to two times the laboratory upper limit of normal) were higher in the risperidone group (79 percent) than in the asenapine or placebo groups (9 percent and 2 percent, respectively). Asenapine-treated patients reported a lower rate of clinically significant weight gain (greater than or equal to 7 percent) versus risperidone-treated patients (4.3 percent versus 17 percent; 1.9 percent for placebo).

In the study, asenapine 5 mg twice daily was significantly more effective than placebo in improving both positive and negative symptoms associated with schizophrenia, based on the Positive and Negative Syndrome Scale (PANSS). This difference was seen starting at the second week of treatment.

"Currently available atypical antipsychotic drugs like risperidone are effective at reducing hallucinations and other positive symptoms associated with schizophrenia," said Steven G. Potkin, MD, Department of Psychiatry and Human Behavior, University of California, Irvine. "Asenapine's effect on negative symptoms, as seen in our trial, is an interesting finding.