The dosage-dependent effects of cevimeline in preventing clozapine-induced dyslipidaemia in female rats

Clozapine is the most effective second-generation antipsychotic drug, especially for the therapy of treatment-resistant schizophrenia. However, it is associated with metabolic side-effects. Clozapine has a high antagonistic affinity to muscarinic M3 receptors, which has been reported to play a significant role in these side-effects. This study aimed to investigate whether co-administration of cevimeline (an M3 receptor agonist) could prevent the metabolic disorders induced by clozapine. Female Sprague Dawley rats were treated orally with clozapine (20 mg/kg, 3 times daily) and/or cevimeline at three dosages (3, 6, 9 mg/kg, 3 times daily), or a vehicle for two weeks. Body weight gain, food/water intake, and temperature were recorded. Open field tests were performed to assess motor activity. Clozapine only treatment significantly decreased body weight gain, feeding efficiency, perirenal, periovary, inguinal, total white fat mass, and NEFA levels. The reduction in body weight gain and feeding efficiency caused by clozapine was partially reversed by co-treatment with 3 or 6 mg/kg cevimeline. Clozapine also significantly increased the liver mass, LDL, and HDL level, which were reversed by the co-treatment with cevimeline at all tested dosages. These results support further clinical trials to evaluate cevimeline's potential in controlling clozapine-induced dyslipidemia.