Evaluation of the drug utilization pattern at a regional psychiatric hospital, in Benin city, Nigeria

Background: Drug utilization research facilitates the rational use of drugs and suggests measures to improve prescribing habits. Irrational use of drugs is a global problem affecting patient care. It results in increased mortality, morbidity, adverse drug events, and wastage of economic resources. Objectives: To evaluate the pattern of drug utilization at a regional neuropsychiatric hospital, in Benin City, Nigeria using some of the World Health Organization (WHO) prescribing indicators. Materials and Methods: Data was obtained retrospectively from a review of 5400 outpatient prescriptions between September 2007 and August 2012. Data were analyzed using the WHO guideline for assessment of drug use in health facilities. The number of DDD per one thousand inhabitants per day was calculated from data on the number and size of dispensed drugs obtained from the out-patient pharmacy. Drug Utilization 90% (DU 90%) method was used to evaluate the quality of drug prescribing. Results: An average of 2.88 drugs was prescribed per encounter, 94.38% of the drugs were prescribed using their generic names, and the percentage of encounters with antibiotics prescribed was 3.2% while 99.2% of all the drugs prescribed were prescribed from the essential drugs list. The drugs whose utilization accounted for about 90% of the entire drug use (DU 90%) were; haloperidol (15.5%), amitriptyline (22.3%), benzhexol (12.6%), trifluoperazine (20.3%), chlorpromazine (15.2%), and carbamazepine (7.9%). Haloperidol was the most utilized drug in this setting with a DDD per 1000 inhabitants per day of 5. In about 70% of the prescriptions encountered, all the drugs prescribed were available from the hospital pharmacy. Conclusion: This study found that polypharmacy was commonly practiced while haloperidol was the most utilized psychotropic agent at the study facility.