Should obesity be a limiting factor for clozapine treatment?

Clozapine is the first choice in drug-resistant schizophrenia but also causes important weight changes. This might discourage clinicians concerned about the risk of developing health problems. To assess this issue we measured change in body mass index (cBMI) induced by clozapine at 18 and 56 weeks.

Baseline body weight and height were measured and weight weekly thereafter during the first 18 weeks of treatment. After that, measurements were made monthly. Steady clozapine dose, clozapine and norclozapine blood concentrations, concomitant medication, gender and age were recorded.

At 18 weeks (n=76) mean cBMI was 1.83 kg/m(2). Baseline BMI was inversely correlated with cBMI. At 56 weeks (n=57) cBMI was 2.67 kg/m(2) and was inversely correlated with basal BMI. Multiple regression analysis replicated the results. When split with BMI categories, obese patients had lesser risk for further weight gain.

Obesity should not discourage clinicians from starting clozapine in drug-resistant patients.