Drug utilization study of off-label drug use in outpatient department of psychiatry: a prospective study at a tertiary care teaching hospital

Background: In the absence of standard psychiatric prescribing information, physician often use drugs in an off-label way. Many studies have been published across the globe reporting different rates of off-label use. There is currently no study based on Indian Drug Formulary.Methods: After taking permission from Institutional Ethics Committee (IEC), a prospective study was conducted among 285 patients attending Psychiatry outpatient department for the period of 4 months. Data related to demographic parameters, diagnosis of psychiatry conditions and drugs details were collected directly from the patient's medical records and entered in Case Record Form (CRF).The off-label drugs were categorized as per National Formulary of India. Multivariate binary logistic regression model was used to determine the predictors of off- label drug prescribing. The data were statistically analyzed using SPSS version 19 and chi-square test.Results: A total of 285 patients (169 males, 116 females) were included in the study with mean age of 36.54±13.91 years. Most of the patients (n=65, 22.8%) were diagnosed as schizophrenic. Out of 285 patients, 133(46.6%) received at least one off-label drug. A total 841 drugs were prescribed out of which 167(19.85%) were off-label. The drug most frequently prescribed as off-label were trihexiphenidyl HCL 29 (10.2%), clozapine 23 (8.1%) and clonazepam 13 (4.6%).Conclusions: Off label drugs used among psychiatry patients was 19.85%. The most frequently used off-label drugs was trihexiphenidyl HCL. The use of off-label drugs in psychiatric patients has been reportedly increasing which warrant national drug regulatory authorities to review and revise safe administration such drugs.