Pharmacist-led Review of Drug Utilization of Antipsychotic Medications in a Tertiary Government Hospital in Cebu City, Philippines

Background. Mental health remains a significant public health concern in the Philippines, with schizophrenia posing major burdens on individuals, families, and society. Antipsychotic drugs are still the most effective treatment. However, the prevalence of irrational drug use in psychiatric patients, including antipsychotic polypharmacy and non-adherence, has been associated with negative outcomes such as increased adverse effects, rehospitalization, higher cost, and impaired quality of life. To address this, drug utilization studies are crucial for developing strategies to optimize healthcare resource use, address drug use issues, promote rational prescribing, and improve patient access. Objectives. The study evaluated the prescribing patterns of antipsychotic medications among inpatients with schizophrenia in a tertiary government hospital in Cebu City, Philippines, which aimed to identify patterns of drug use, potential drug therapy problems, and examine the appropriateness of use. Methods. The study utilized a retrospective observational design. A review of medical records was carried out from January 1, 2022, to December 31, 2022. Data collected includes patient demographics, diagnosis, and prescribed antipsychotic medications. Descriptive statistics in Microsoft Excel® were used to report findings, and a Poisson regression model in IBM SPSS Software version 25 was used to analyze the data. Results. A total of 109 patient medical records were screened, with 33 records selected based on the inclusion criteria. Risperidone (35.4%) was the most prescribed antipsychotic drug. A higher inclination towards the use of second-generation antipsychotics was observed than first-generation antipsychotics. Paliperidone palmitate injection had the highest consumption (4.8056 defined daily doses/100 bed days) among the antipsychotics. It was found that underinvestment in newer medications limits patient access. Significant relationships were found between the number of drugs per medication order and male gender (p = 0.002) and substance abuse disorder (p = 0.07). The average number of antipsychotic drugs prescribed per medication record was 1.97, while the average number of drugs per patient was 3.82. All the medications were prescribed by their generic names and sourced from the Philippine National Drug Formulary. Injectable drugs accounted for 19.05% of the total medications. Drug therapy problems, such as drug–drug interactions (82%) and therapeutic duplication (58%), were prevalent. There were substance use disorders (9.09%) as a comorbidity among patients studied. Conclusion. There is a prescribing trend towards secondgeneration antipsychotics, with risperidone being the most frequently prescribed antipsychotic medication. Utilization patterns of antipsychotics generally conformed to the WHO standard recommendations. This study highlights the high consumption of paliperidone palmitate injection, which calls for further research on antipsychotic consumption in patients with comorbid substance use disorder. Strengthening pharmacist involvement in patient care alongside policy-driven approaches can improve access, optimize therapy, and ensure quality antipsychotic medication use.