Factors predicting use of laxatives in outpatients stabilized on clozapine

TY - JOUR

T1 - Factors predicting use of laxatives in outpatients stabilized on clozapine

AU - Bailey, Loren

AU - Varma, Seema

AU - Ahmad, Nina

AU - Gee, Siobhan

AU - Taylor, David M

PY - 2015/10

Y1 - 2015/10

N2 - Constipation is a common and sometimes fatal side effect of clozapine treatment. In this study, we aimed to identify factors associated with clozapine-induced constipation. Data on 202 outpatients stabilized on clozapine treatment were collected. Of these, 71 patients (35%) had a current prescription for laxatives (a proxy for the presence of constipation). Mean clozapine dose was 400.4 mg/day in those prescribed laxatives and 390.1 mg/day in those not prescribed laxatives (p = 0.67), while mean clozapine plasma concentration was 0.53 mg/l and 0.49 mg/l, respectively (p = 0.29). Patients using laxatives had on average 29% higher norclozapine concentrations (mean = 0.34 mg/l) than those who did not use laxatives (mean = 0.27 mg/l; p = 0.046). Laxative use was more common in female patients (49.1%) than male patients (29.1%; p < 0.01). Prescribers should be vigilant for constipation at any dose or plasma concentration of clozapine and should be mindful that male patients may be undertreated. Norclozapine concentrations may predict clozapine-induced constipation.

AB - Constipation is a common and sometimes fatal side effect of clozapine treatment. In this study, we aimed to identify factors associated with clozapine-induced constipation. Data on 202 outpatients stabilized on clozapine treatment were collected. Of these, 71 patients (35%) had a current prescription for laxatives (a proxy for the presence of constipation). Mean clozapine dose was 400.4 mg/day in those prescribed laxatives and 390.1 mg/day in those not prescribed laxatives (p = 0.67), while mean clozapine plasma concentration was 0.53 mg/l and 0.49 mg/l, respectively (p = 0.29). Patients using laxatives had on average 29% higher norclozapine concentrations (mean = 0.34 mg/l) than those who did not use laxatives (mean = 0.27 mg/l; p = 0.046). Laxative use was more common in female patients (49.1%) than male patients (29.1%; p < 0.01). Prescribers should be vigilant for constipation at any dose or plasma concentration of clozapine and should be mindful that male patients may be undertreated. Norclozapine concentrations may predict clozapine-induced constipation.

U2 - 10.1177/2045125315591917

DO - 10.1177/2045125315591917

M3 - Article

C2 - 26557981

SN - 2045-1253

VL - 5

SP - 256

EP - 262

JO - Therapeutic Advances in Psychopharmacology

JF - Therapeutic Advances in Psychopharmacology

IS - 5

ER -