Acute hemorrhagic colitis induced by the oral administration of oseltamivir used for influenza A treatment

Considerations when treating influenza infections with oseltamivir

INTRODUCTION

Since the coronavirus disease 2019-mandated social distancing policy has been lifted worldwide, the circulation of influenza is expected to resume. Currently, oseltamivir is approved as the first-line agent for influenza prevention and treatment.

AREAS COVERED

This paper reviews the updated evidence in the pharmacology, resistance mechanisms, clinical pharmacy management, and real-world data on oseltamivir for influenza.

EXPERT OPINION

Oseltamivir is an oral prodrug of oseltamivir carboxylate, an influenza A and B neuraminidase inhibitor. Recently, the therapeutic efficacy of oseltamivir has been demonstrated in several trials. Oseltamivir is generally well-tolerated but may lead to neuropsychiatric events and bleeding. Oseltamivir-resistant influenza virus has been associated with the H275Y mutation in the influenza A(H1N1)pdm09 virus, while most strains are still sensitive to oseltamivir. Dose adjustment for oseltamivir should be based on creatinine clearance and body weight in pediatric patients with renal failure. According to real-world data from Nanfang Hospital, the annual number of patients prescribed oseltamivir declined from 35,711 in 2019 to 8,971 in 2020, with marked increases in 2022 (20,213) and 2023 (18,071). Among the 206 inpatients, children aged < 6 years who were treated with oseltamivir had the shortest duration to defervescence.

Antiviral influenza treatments and hemorrhage-related adverse events in the United States Food and Drug Administration Adverse Event Reporting System (FAERS) database

STUDY OBJECTIVE

To determine whether there is a signal for gastrointestinal (GI) or intracranial (IC) hemorrhage associated with the use of antiviral medications for influenza in the US Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) database.

DESIGN

Disproportionality analysis.

DATA SOURCE

The FAERS database was searched using OpenVigil 2.1 to identify GI and IC hemorrhage events reported between 2004 and 2022.

MEASUREMENTS

Antiviral medications for influenza included the following: oseltamivir, zanamivir, peramivir, and baloxavir marboxil. Hemorrhage events were identified using Standardized Medical Dictionary for Regulatory Activities (MedDRA) Queries for GI and IC hemorrhages. Reporting odds ratios (RORs) were calculated to compare the occurrence of GI and IC hemorrhage events between antiviral drugs for influenza and (i) all other medications and (ii) antibiotics. RORs were also calculated for each of the individual antiviral medications.

MAIN RESULTS

A total of 245 cases of GI hemorrhage and 23 cases of IC hemorrhage were identified in association with four antivirals. In comparison with all other drugs, the RORs of GI hemorrhage for oseltamivir, zanamivir, peramivir, baloxavir, and all antivirals combined were 1.17, 0.62, 4.44, 2.53, and 1.22, respectively, indicating potential variations in GI hemorrhage risk among the antivirals. In contrast, in comparison with all other drugs, the RORs of IC hemorrhage for oseltamivir (0.44), zanamivir (0.16), baloxavir (0.44), and all antivirals combined (0.41) were less than 1.0 which is consistent with no elevated risk of IC hemorrhage.

CONCLUSION

In this study, some signals for GI hemorrhage were observed, particularly for peramivir and baloxavir marboxil. Further investigation is warranted to better understand and evaluate the potential risks of GI hemorrhage associated with antiviral treatments for influenza.

Laninamivir-induced ischemic enterocolitis: A case report

BACKGROUND

Neuraminidase inhibitor-associated acute hemorrhagic colitis is rare. We report a case of ischemic enterocolitis that was likely caused by laninamivir.

CASE SUMMARY

A 54-year-old female patient with influenza type A was administered 40 mg of laninamivir via inhalation once. On the same day, the patient experienced bloody stools and lower abdominal pain. A contrast-enhanced abdominal computed tomography showed edema-like changes from the descending colon to the sigmoid colon, which suggested ischemic enterocolitis.

CONCLUSION

We treated a patient with ischemic enterocolitis caused by laninamivir, a rare but similar symptom following the administration of oseltamivir.

Comparison of the incidence of bleeding between baloxavir marboxil and other anti-influenza drugs among outpatients with influenza virus infection: A retrospective cohort study using an employment-based health insurance claims database in Japan

Purpose

Alerts for bleeding events are included in the Japanese package inserts of some anti‐influenza drugs, including baloxavir marboxil and oseltamivir. However, there are few reports on the incidence of bleeding events during treatment with anti‐influenza drugs. This large‐scale quantitative assessment compared the incidence of bleeding events in influenza patients treated with baloxavir and other anti‐influenza drugs and in untreated patients.

Methods

This retrospective cohort study used a large‐scale Japanese employment‐based health insurance claims database provided by JMDC Inc. and included outpatients diagnosed with influenza between October 1, 2018 and April 11, 2019. Bleeding events were identified by International Classification of Diseases 10th revision codes. Incidences were compared between patients treated with baloxavir or neuraminidase inhibitors and untreated patients. Odds ratios were calculated after exact matching to adjust for potential confounders.

Results

Among 529 201 influenza episodes, 30 964 were untreated and 498 237 were treated with anti‐influenza drugs: baloxavir, 207 630; oseltamivir, 143 722; zanamivir, 28 208; peramivir, 5304; laninamivir, 113 373. Crude incidence proportions for total bleeding up to 20 days after influenza diagnosis were similar among treated groups, with a slightly higher value for peramivir (0.21% vs. 0.19% for baloxavir, oseltamivir, zanamivir, and laninamivir), and 0.30% in untreated patients. After exact matching, the incidence of bleeding for baloxavir was similar to that for other anti‐influenza treatments (odds ratios for baloxavir were 0.90–0.99 compared to other therapies).

Conclusions

Based on real‐world observation using a large‐scale claims database, a similar incidence of bleeding events was observed in recipients of the different anti‐influenza drugs.

Case report on alimentary tract hemorrhage and liver injury after therapy with oseltamivir: A case report

RATIONALE

Oseltamivir-induced alimentary tract hemorrhage and liver injury are rarely reported in children and adult individuals. In this study, we described the clinical features and outcomes of oseltamivir-induced alimentary tract hemorrhage and liver injury in a child.

PATIENT CONCERNS

Here, we present a case of a 6-year-old Asian boy with hematemesis and elevated alanine aminotransferase (ALT) (80 U/L) and aspartate aminotransferase (AST) (69 U/L) levels on day 2 of oseltamivir administration. The presence of alimentary tract hemorrhage and liver injury was diagnosed. The ALT level reached 1931.3 U/L, accompanied by an increase in total bilirubin (TBIL) to 53.3 μmol/L on day 15 after oseltamivir administration. Additional tests were performed to determine the presence of viruses that can cause hepatitis and autoantibodies, and the results from these tests were all negative.

DIAGNOSIS

Drug-induced liver injury was considered.

INTERVENTIONS

This patient was treated with compound glycyrrhizin and reduced glutathione and glucocorticoid.

OUTCOMES

The liver enzymes recovered within 6 weeks without any symptoms of liver-related diseases after treatment with glucocorticoid. This treatment therefore helps reduce ALT and TBIL levels and protects the liver from further injury.

LESSONS

Oral oseltamivir is widely used to treat influenza and the adverse effects of this drug were mostly mild. However, clinicians should always be alert for oseltamivir-induced alimentary tract hemorrhage and liver injury when prescribing oseltamivir for children.

Long-term detection of seasonal influenza RNA in faeces and intestine

Some cases of seasonal influenza virus (human influenza A virus (IAV)/human influenza B virus (IBV)) are associated with abdominal symptoms. Although virus RNA has been detected in faeces, intestinal infection has not been clearly demonstrated. We aimed to provide evidence that IAV/IBV infects the human intestine. This prospective observational study measured virus RNA in faecal and sputum samples from 22 patients infected with IAV/IBV (19 IAV positive and three IBV positive). Nineteen patients were included in the analysis and were assigned to faecal IAV-positive and -negative groups. Virus kinetics were examined in faecal samples from an IAV-infected patient (patient 1) and an IBV-infected patient (patient 2). Finally, intestinal tissue from an IAV-diagnosed patient who developed haemorrhagic colitis and underwent colonoscopy was examined for the presence of replicating IAV (patient 3). Virus RNA was detected in faecal samples from 8/22 IAV/IBV-infected patients (36.4%). Diarrhoea occurred significantly more often in the faecal IAV-positive group (p 0.002). In patients 1 and 2, virus RNA became undetectable in sputum on days 7 and 10 after infection, respectively, but was detected in faeces for a further 2 weeks. Virus mRNA and antigens were detected in intestinal tissues (mucosal epithelium of the sigmoid colon) from patient 3. These findings suggest that IAV/IBV infects within the intestinal tract; thus, the human intestine may be an additional target organ for IAV/IBV infection.

An empirical approach towards the efficient and optimal production of influenza-neutralizing ovine polyclonal antibodies demonstrates that the novel adjuvant CoVaccine HT™ is functionally superior to Freund's adjuvant

Passive immunotherapies utilising polyclonal antibodies could have a valuable role in preventing and treating infectious diseases such as influenza, particularly in pandemic situations but also in immunocompromised populations such as the elderly, the chronically immunosuppressed, pregnant women, infants and those with chronic diseases. The aim of this study was to optimise current methods used to generate ovine polyclonal antibodies. Polyclonal antibodies to baculovirus-expressed recombinant influenza haemagglutinin from A/Puerto Rico/8/1934 H1N1 (PR8) were elicited in sheep using various immunisation regimens designed to investigate the priming immunisation route, adjuvant formulation, sheep age, and antigen dose, and to empirically ascertain which combination maximised antibody output. The novel adjuvant CoVaccine HT™ was compared to Freund’s adjuvant which is currently the adjuvant of choice for commercial production of ovine polyclonal Fab therapies. CoVaccine HT™ induced significantly higher titres of functional ovine anti-haemagglutinin IgG than Freund’s adjuvant but with fewer side effects, including reduced site reactions. Polyclonal hyperimmune sheep sera effectively neutralised influenza virus in vitro and, when given before or after influenza virus challenge, prevented the death of infected mice. Neither the age of the sheep nor the route of antigen administration appeared to influence antibody titre. Moreover, reducing the administrated dose of haemagglutinin antigen minimally affected antibody titre. Together, these results suggest a cost effective way of producing high and sustained yields of functional ovine polyclonal antibodies specifically for the prevention and treatment of globally significant diseases.