A Retrospective Drug Utilization Study of Antidepressants in the Psychiatric Unit of a Tertiary Care Hospital

Introduction: Drug utilization is the marketing, distribution, prescription and the use of drugs in a society. Antidepressant prescribing patterns have changed globally over the last few years. Hence, we wanted to observe the prescribing pattern of antidepressants at our hospital and assess the rationality of the prescriptions and the prevalence of antidepressant usage in the community. Methods: A retrospective, observational analysis of the case records of patients who received antidepressant prescriptions at the Psychiatry outpatients clinic of a tertiary care hospital during the period from 1st January 2006 to 31st December 2006, to study the pattern and the rationality in prescription of antidepressant drugs, the WHO prescribing indicators, the Defined daily dose (DDD)/1000/day ( DID), the Prescribed daily dose (PDD) and the PDD to DDD ratio. Results: Antidepressants were prescribed in 76.18% prescriptions (duloxetine-50%, escitalopram - 22.40%, mirtazapine - 17.19%, sertraline - 6.77% and others - 3.64%). The average number of drugs/prescription was 2.32, the number of drugs which were prescribed by their generic names was 88.54% and the number of drugs which were prescribed from WHO EML was 1.56%. There were no prescriptions for FDCs or injectibles. The DID of the antidepressants was 0.02 mg. The PDD to DDD ratios were < 1 for duloxetine and mirtazapine; for others, they were >= 1. Conclusion: Antidepressants were the most commonly prescribed psychotropic medicines. Duloxetine, escitalopram, mirtazapine and sertraline were the most commonly used ones. The prescriptions were complete and without polypharmacy. Favourable and unfavourable outcomes were seen for 3 and 2 WHO prescribing indicators respectively. The antidepressant consumption in the community was low. Adequate dosing was seen for all the antidepressants, except for duloxetine and mirtazapine (under-dosing). Adherence to standard treatment guidelines, choosing drugs from the EML and restricting the prescription of concomitant sedative hypnotics will decrease the number of drugs and the cost of the therapy and they will promote the rational use of medicines.