Drug-drug interactions in the ICU

EVALUATING THE IATROGENIC EFFECTS OF POLYPHARMACY AND DRUG INTERACTIONS IN HIV-POSITIVE PATIENTS ADMITTED TO THE INTENSIVE CARE UNIT: A SINGLE-CENTER RETROSPECTIVE STUDY

Background. Polypharmacy and drug interactions are of particular concern in people living with HIV/AIDS, especially those who receive antiretroviral therapy (ARVs). Polypharmacy and drug-drug interactions (DDIs) can impact the efficacy and toxicity of HIV treatment. ARVs used in HIV treatment are often prone to drug interactions if administered with other non-ARV drugs because many of them are metabolized through the cytochrome P450 system. The pharmacological management of HIV patients in the intensive care unit (ICU) is usually complex and typically involves the administration of several classes of drugs. This patient group may be at higher risk for potential DDIs due to polypharmacy in the ICU. Objectives. The main objective of this study was to assess the iatrogenic effects of polypharmacy in HIV patients treated in the ICU and to describe the DDI profile between ARVs and other non-ARV medications prescribed in the ICU. Methods and materials. Between 2018 and 2020, we conducted a single-center, retrospective study evaluating the medical records of 59 HIV patients admitted to the ICU for more than 24 hours at the Infectious Disease Clinical Hospital № 2, Moscow, Russia. We evaluated the impact of polypharmacy on renal, hepatic and haemopoietic function. The Liverpool HIV Drug Interaction database was used to identify DDIs in ART-treated HIV patients. Results. All patients received more than 5 different medications matching the definition of polypharmacy. The average number of concurrent medications prescribed was 15 6.713 (maximum 40, minimum 6). All drug interactions recorded were between ARVs and antibiotics: 30 cases of potential interactions in 65.5% patients who received ARV. Of such patients, 94% were exposed to at least two potential interactions. Tenofovir (TDF) and the antibiotic vancomycin underlaid the most common potential interaction (49.2%), followed by lopinavir ritonavir (LPV/RTV) and ciprofloxacin (30.3%). A significant difference in average creatinine levels was found in patients with TDF/vancomycin potential interactions (p 0.05). Conclusion. This study demonstrated that potential DDIs frequently occur in ICU patients in line with previous investigations. It is necessary to implement collaborations among clinical pharmacologists and infectious disease/HIV specialists, as well as frequent clinical and laboratory monitoring, aimed at developing effective and actionable strategies that could reduce potential DDIs in HIV patients in the ICU.

Polypharmacy and emergency readmission to hospital after critical illness: a population-level cohort study

BACKGROUND

Polypharmacy is common and closely linked to drug interactions. The impact of polypharmacy has not been previously quantified in survivors of critical illness who have reduced resilience to stressors. Our aim was to identify factors associated with preadmission polypharmacy and ascertain whether polypharmacy is an independent risk factor for emergency readmission to hospital after discharge from a critical illness.

METHODS

A population-wide cohort study consisting of patients admitted to all Scottish general ICUs between January 1, 2011 and December 31, 2013, whom survived their ICU stay. Patients were stratified by presence of preadmission polypharmacy, defined as being prescribed five or more regular medications. The primary outcome was emergency hospital readmission within 1 yr of discharge from index hospital stay.

RESULTS

Of 23 844 ICU patients, 29.9% were identified with polypharmacy (n=7138). Factors associated with polypharmacy included female sex, increasing age, and social deprivation. Emergency 1-yr hospital readmission was significantly higher in the polypharmacy cohort (51.8% vs 35.8%, P<0.001). After confounder adjustment, patients with polypharmacy had a 22% higher hazard of emergency 1-yr readmission (adjusted hazard ratio 1.22, 95% confidence interval 1.16-1.28, P<0.001). On a linear scale of polypharmacy each additional prescription conferred a 3% increase in hazard of emergency readmission by 1 yr (adjusted hazard ratio 1.03, 95% confidence interval 1.02-1.03, P<0.001).

CONCLUSIONS

This national cohort study of ICU survivors demonstrates that preadmission polypharmacy is an independent risk factor for emergency readmission. In an ever-growing era of polypharmacy, this risk factor may represent a substantial burden in the at-risk post-intensive care population.