Off-label drug use in Psychiatry Outpatient Department: A prospective study at a Tertiary Care Teaching Hospital.

Introduction: Off-label drug prescribing is very common in Psychiatry.US-Food and Drug Administration has defined off-label drug as "use of drugs for the indication, dosage form, regimen, patient or other use constraint not mentioned in the approved labeling." Objective: The objective was to evaluate off-label drug use in patients attending Outpatient Department of Psychiatry. Materials and Methods: One year prospective, cross sectional study was conducted on patients attending Psychiatry Outpatient Department. Demographic data, clinical history, and complete prescription were noted in the predesigned proforma and prescriptions were analyzed for off-label drug use as per British National Formulary-2011. Result: A total of 250 patients were enrolled with mean age 40.36 ± 12.3 years. Most common diagnosis was major depressive disorder 101 (40.4%). A total of 980 drugs (mean 3.68 ± 1.42) were prescribed out of which 387 (39.5%) were off-label. Of 250 patients, 198 (79.2%) received at least one off-label drug. Psychopharmacological agents most frequently used in off-label manner were clonazepam 31 (12.4%), lorazepam 30 (12%), and trihexyphenidyl HCl 25 (10%). Prevalence of off-label use of these three drugs was significantly higher than other off-label drugs (P < 0.0001, P < 0.0001 and P < 0.0001 respectively). Inappropriate indication was the most common category of off-label use. There was positive and significant correlation between off-label prescribing and number of drugs (r = 0.722, P ≤ 0.000). Off-label prescribing was statistically significantly higher in 21-40 year age group, but no difference was seen in any co-morbid condition or in between any psychiatric disorder. Conclusion: Off-label drugs use is common in psychiatric OPD in our setup. Clonazepam, lorazepam, and trihexyphenidyl HCl were the most frequently used drugs in off-label manner.