Pharmacist's role in the management of drug-drug interactions caused by nirmatrelvir/ritonavir in COVID-19 oncohematology patients.

OBJECTIVE: New drugs developed for SARS-CoV-2 infection, such as nirmatrelvir/ritonavir (NMV/r), represent a potential for oncohematology patients, but also pose a challenge in managing the potential clinically relevant drug-drug interactions (pDDIs) that may arise. The aim of this study is to assess the frequency, severity, and pharmacist detection of pDDIs. METHODS: This prospective, observational, study spanned 8 months, involving 42 oncohematology patients prescribed NMV/r in a tertiary-level hospital. A Board Certified oncology pharmacist assessed pDDIs using three databases and made recommendations to prescribing physicians. Linear and logistic regression analyses were employed to explore the relationship between prescribed drugs and pDDIs. RESULTS: Clinically relevant pDDIs were detected in 76.2% of patients, with 18.1% of all medications involved in drug-drug interactions (DDIs). The most common drugs implicated were atorvastatin and imatinib. Micromedex® identified 63.3% of interactions as major severity, while Lexicomp® and University of Liverpool classifications were less restrictive. Pharmacists prevented most DDIs from reaching patients through different interventions, including treatment monitoring (44.2%), discontinuation (36.5%), and dose reduction (17.3%). CONCLUSION: This study highlights the high prevalence of clinically significant pDDIs in oncohematology patients receiving NMV/r for COVID-19. Pharmacists, as integral members of the healthcare team, played a crucial role in detecting, categorizing, and mitigating these interactions. The results underscore the need for comprehensive studies to evaluate the impact of pharmacist-led interventions in optimizing drug therapy and enhancing patient safety in this vulnerable population.

Management of nirmatrelvir/ritonavir and tacrolimus interaction in kidney transplant recipients infected by COVID-19: a three-case series.

OBJECTIVES: Nirmatrelvir/ritonavir may cause a clinically relevant drug-drug interaction (DDI) with immunosuppressive drugs, such as tacrolimus, which may condition the use of this antiviral in transplant patients. We aimed to describe the management of this interaction. METHODS: Descriptive study in which renal transplant patients in treatment with nirmatrelvir/ritonavir and tacrolimus were included. They suspended tacrolimus the day before starting the antiviral treatment, and the decision to restart it was made based on their tacrolimus blood levels. Main variables studied to measure this DDI were tacrolimus blood concentration, dose adjustment and serum creatinine. RESULTS: Three patients were included. During the study, tacrolimus levels elevation did not have repercussion in the serum creatinine, that remained stable in all patients. No patient required hospitalisation or showed signs of rejection. CONCLUSIONS: Our experience provides further evidence that this interaction should not be a contraindication to treatment with nirmatrelvir/ritonavir, and can be managed with close monitoring of tacrolimus levels.