Weight and blood pressure change during clozapine treatment.

We examined whether clozapine-related weight gain is associated with an increase in mean arterial blood pressure. Weight gain and mean arterial blood pressure changes were assessed in 61 outpatients with schizophrenia who were randomly assigned to either clozapine or haloperidol in a 10-week parallel group, double-blind study and in 55 patients who chose to continue to receive clozapine in a subsequent 1-year open-label prospective study. Clozapine treatment was associated with significant weight gain in the double blind and open-label trials. Haloperidol treatment was not associated with significant weight gain. Neither clozapine nor haloperidol treatment were associated with significant changes in mean arterial blood pressure. There were no significant correlations between weight gain and mean arterial blood pressure change with either medication. Although clozapine treatment is associated with weight gain, the correlation between this weight gain and increases in arterial blood pressure during the first year of treatment appears to be low.