Potential Drug-Drug Interactions among Patients with Schizophrenia Spectrum Disorders: Prevalence, Association with Risk Factors, and Replicate Analysis in 2021

Abstract

Background and Objectives: Patients with schizophrenia are often exposed to polypharmacotherapy, which may lead to drug—drug interactions. The aim of the study was to investigate the prevalence of potential drug—drug interactions (pDDIs) in hospitalized patients with schizophrenia spectrum disorders and to identify factors associated with pDDIs and manifested symptoms and signs. Materials and Methods: This cross-sectional observational study included 311 inpatients admitted to a psychiatric hospital. The LexiComp drug interaction program was used to identify pDDIs in 2014. Factors associated with the prevalence of pDDIs and factors related to clinically observed symptoms and signs were assessed using multivariable regression. In addition, replicate analysis of pDDI was performed using 2021 program updates. Results: The prevalence of pDDIs was 88.7%. Our study showed that more than half of the patients received at least one drug combination that should be avoided. The most common pDDIs involved combinations of two antipsychotics or combinations of antipsychotics and benzodiazepines, which can lead to cardio-respiratory depression, sedation, arrhythmias, anticholinergic effects, and neuroleptic malignant syndrome. The number of prescribed drugs was a risk factor for pDDIs (OR 2.85; 95% CI 1.84–5.73). All groups of clinically observed symptoms and signs were associated with the number of drugs. In addition, symptoms and signs characteristic of the nervous system and psychiatric disorders were associated with antipsychotic dosage (IRR 1.33; 95% CI 1.12–1.58), which could contribute to the development of extrapyramidal syndrome, insomnia, anxiety, agitation, and bipolar mania. The 2021 version of the drug interaction program showed a shift in drug interactions toward a lower risk rating, implying less severe patient management and possibly less alert fatigue. Conclusions: Patients with schizophrenia spectrum disorders are at high risk of developing drug—drug interactions. Optimization of drug therapy, patient monitoring, and use of drug interaction programs could help to prevent pDDIs and subsequent adverse drug events.

Infections associated with clozapine: a pharmacovigilance study using VigiBase®

“…Patients with schizophrenia often receive polypharmacotherapy, exposing them to potential drug–drug interactions (DDIs). A cross-sectional observational study in a psychiatric hospital found a high prevalence (88.7%) of potential DDI in this population ( Bačar Bole et al, 2023 ). Clozapine is metabolized by various CYP450 enzymes, including CYP1A2, CYP3A4, CYP2D6, CYP2C9, and CYP2C19 ( Chetty and Murray, 2007 ; Pardiñas et al, 2019 ).…”

Drug Selection, Dosage Adjustment, and Potential Interaction of Antihypertensive and Antidiabetic for Chronic Kidney Disease with Hemodialysis

“…Another study also found no significant relationship between gender and age with potential drug interactions (44) . However, studies in Ethiopia and Pakistan, Slovenia, Brazil found a significant relationship between the number of drugs and the potential for drug interactions, where an increase in the number of drugs corresponded to an increase in the potential for drug interactions (45)(46)(47) . The difference in results could be due to the potential drug interactions studied in our study focusing only on the potential drug interactions involving antihypertensive and antidiabetic drugs.…”

Medication Dosage Impact on Mortality in Old-Age Individuals with Schizophrenia: A National Cohort Study

“…Pharmacological treatments are available for management of OAS but may be limited by tolerability, presence of physical comorbidities, and potential adverse effects of polypharmacy [ 5 , 6 ]. A more recent study has indicated that patients with old-age onset schizophrenia share a unique clinical course and treatment response compared to the general schizophrenia population [ 7 , 8 ].…”