Effects of Trigger Tools for Detecting Extrapyramidal Side Effects from Antipsychotic Drugs in Thanyarak Songkhla Hospital

Abstract

Background: Extrapyramidal side effects (EPS) are common adverse drug reactions from antipsychotic drugs use. Trigger tools are a better method for detecting adverse events than spontaneous reporting. The researchers therefore proposed using trigger tools to identify patients who had developed EPS from antipsychotic drugs in hospital setting. Objective: To study the outcomes of each trigger tool in detecting EPS and to study the incidence of EPS from antipsychotic drugs. Methods: This retrospective study reviewed inpatient medical records after discharge. Four types of trigger tools were examined: 1) Prescription of Benztropine injection, 2) Prescription of Diazepam injection, 3) Initiation or dose increase of Trihexyphenidyl oral, and 4) Initiation or dose increase of Propranolol oral. Medical records where trigger tools were identified were then evaluated for adverse drug reactions using Naranjo’s algorithm. Cases scoring 5 or higher (indicating “probable” or “definite”) were classified as EPS. Data were analyzed using descriptive statistics and Fisher’s exact test, with statistical significance set at p < 0.05. Results: Reviews of 430 medical records found that 26 patients were identified with EPS using trigger tools, which were higher than the spontaneous reporting method of only 2 cases. The initiation or dose increase of Trihexyphenidyl oral was the most frequent trigger leading to EPS detection (23 occurrences). The prescription of Benztropine injection had the highest EPS detection rate (100%). The incidence of EPS was 2.03 per 100 hospitalizations. The most common type of EPS observed was Acute dystonia (24 cases). Conclusion: The use of all four trigger tools increased the detection of EPS from antipsychotic drugs.