Antipsychotic Adverse Reactions in Underweight Patients

Indianapolis, IN

There exists a paucity of evidence to guide the use of antipsychotics (APs) in underweight patients. Alterations in pharmacokinetic and pharmacodynamic properties may increase the risk of adverse drug reactions (ADRs) such as in certain patient groups (e.g. pediatric, geriatric, eating disordered) where low body mass index (BMI) is more prevalent than in the general population. The aim of this study is to determine if there is an increased risk of EPS in underweight patients (BMI < 18.5 kg/m2) taking antipsychotics, and whether an empiric dose reduction may be warranted to improve tolerability and treatment success. A retrospective chart review will be performed including patients with an encounter at Community Health Network (CHNw) who are identified by either an ICD code or an “as needed” (PRN) administration of benztropine (Cogentin®), a medication used to treat medication-induced EPS. Patients will be sorted based on BMI to determine if there is a significant association between BMI and antipsychotic-related EPS. The underweight group will be further stratified for secondary analysis by antipsychotic medication class, agent, subtype of EPS (dystonia, akathisia, parkinsonism, or tardive dyskinesia), and dose (low, medium, or high) to search for relationships within these subgroups that may underlie the mechanism of antipsychotic-related EPS and/or indicate the need for an empiric dose reduction may be appropriate. Additional data points collected to indicate nutritional status will also be assessed to determine if specific characteristics of the underweight population drive this risk. Results and conclusions are on-going at this time.