Source: Ophthalmology  |  Posted 10 years ago

Weight-gain associated with olanzapine and clozapine may be related to these drugs' effect on insulin and leptin levels.

This was the conclusion of a study involving 47 patients carried out by investigators in Sweden. Of these patients, 19 patients received conventional antipsychotics, 14 received clozapine and 14 received olanzapine.

It was found that the median insulin level was significantly higher in olanzapine patients compared with conventional agents. In the clozapine group, insulin levels were positively correlated to the drug serum concentration.

Body mass index (BMI) was elevated in about 50 percent of patients with no difference between the groups. Leptin levels were higher in women than men in the group receiving conventional agents, but not in any other group. This suggests that leptin regulation is altered during olanzapine or clozapine treatment. It was mainly due to an increase of leptin in the males that leptin levels were equalised between sexes in the olanzapine group.

Says Dr. K.I. Melkersson, Department of Psychiatry, St G?rans Hospital, Stockholm, Sweden, "The higher insulin level in the patients receiving olanzapine than in those receiving conventional antipsychotics, despite similar BMI, points to a probable influence of olanzapine on insulin secretion." He added that the insulin level correlation with clozapine shows the influence of clozapine on insulin.

Dr. Melkersson concluded, "We conclude that the influence of olanzapine and clozapine on both insulin and leptin levels might be associated with their weight-gain-inducing ability, while other mechanisms may be involved in the weight gain caused by conventional antipsychotics."