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Study of oseltamivir and paracetamol blood levels in critically ill patients with severe influenza requiring mechanical ventilation

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study focuses on patients with severe influenza (flu) infection who require intensive care and breathing support through a ventilator. The main treatments being studied are oseltamivir (sold under the brand name Tamiflu) and paracetamol. Oseltamivir is a medication used to treat flu infections, while paracetamol is a common pain and fever reducer.

The purpose of this research is to understand how the amount of oseltamivir medicine in the blood affects recovery in severely ill flu patients. The study will look at patients who are receiving oseltamivir through a feeding tube while on breathing support. Researchers will measure the levels of the medicine in patients' blood after 48 hours of treatment.

During the study, patients will receive regular doses of oseltamivir for up to 10 days. Blood samples will be taken to measure medicine levels, and throat swabs will be collected to check for flu virus. The study will track how long patients need breathing support and monitor their recovery over 90 days. This information will help doctors understand if adjusting medicine doses could lead to better treatment outcomes for severely ill flu patients.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial admission and treatment start

    You will be admitted to the intensive care unit (ICU) due to severe flu infection requiring breathing support through a tube (invasive mechanical ventilation).

    Treatment with oseltamivir (Tamiflu) will be started through a feeding tube within the first 24 hours of admission.

    The medication will be given as 75 mg capsules dissolved and administered through the feeding tube.

  2. Step 2

    48-hour assessment

    After 48 hours of treatment, blood samples will be taken to measure the levels of medication in your blood.

    A paracetamol absorption test will be performed to check how well medications are being absorbed through your digestive system.

    Additional blood tests and clinical assessments will be conducted.

  3. Step 3

    Day 5 follow-up

    A sample from your nose and throat will be taken to measure the amount of flu virus.

    Blood samples will be collected to measure medication levels.

    Your response to treatment will be monitored.

  4. Step 4

    Ongoing monitoring

    Your breathing support requirements will be monitored daily.

    Regular blood samples will be taken to check medication levels on days 2, 3, and 5.

    Your overall health status will be continuously monitored.

  5. Step 5

    Follow-up assessments

    Your health status will be evaluated at day 28 after admission.

    A final assessment will be conducted at day 90.

    The study will track your recovery progress and overall outcomes.

Who can join the trial?

10 criteria

  • Must be 18 years of age or older
  • Must have confirmed severe influenza infection requiring intensive care with:
    • Need for breathing support through a tube inserted into the windpipe (tracheal intubation)
    • May include influenza-related lung failure (ARDS), heart and breathing problems, or heart muscle inflammation (myocarditis)
    • Must have started treatment with oseltamivir (an antiviral medication) through a feeding tube within the past 24 hours, with no more than two doses given
    • Must have active social security coverage (excluding AME)
    • Must provide one of the following:
      • Written consent from the patient
      • Consent from a designated support person
      • Consent from an informed family member
      • Emergency inclusion procedures when consent cannot be obtained
      • Both men and women are eligible to participate

Who cannot join the trial?

10 criteria

  • Patients who are not admitted to Intensive Care Unit (ICU)
  • Individuals who do not require mechanical ventilation (breathing support through a tube inserted into the windpipe)
  • Patients under 18 years of age (not adults)
  • People who do not have confirmed severe influenza infection
  • Patients who cannot receive oseltamivir carboxylate (antiviral medication) treatment
  • Individuals who cannot provide informed consent either directly or through a legal representative
  • Patients who have been intubated (had breathing tube inserted) for more than 48 hours before potential study enrollment
  • Pregnant women, unless specifically approved by their healthcare provider
  • Patients with known allergies to the study medication
  • Individuals participating in other clinical trials that could interfere with this study
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Investigated drugs

Oseltamivir is an antiviral medication used to treat and prevent influenza (flu). It works by stopping the flu virus from spreading inside the body. The medication is converted in the body to its active form called oseltamivir carboxylate. It helps reduce flu symptoms such as fever, cough, and body aches, and may shorten the duration of illness. This medication is particularly important for patients with severe flu infections who require intensive care treatment.

What is already known about the treatment

Oseltamivir Carboxylate - An active form of oseltamivir, administered orally or through a feeding tube, which is widely used in the treatment of severe influenza infections, particularly in intensive care settings. This antiviral medication works by blocking the neuraminidase enzyme on the surface of influenza viruses, preventing them from spreading to other cells in the body, and belongs to the class of neuraminidase inhibitors. The drug has been extensively studied in clinical settings and is particularly important for critically ill patients requiring mechanical ventilation, with its plasma concentration levels being crucial for optimal therapeutic outcomes in severe influenza cases.

Investigated diseases

  • Severe Influenza

    A serious form of respiratory infection caused by influenza viruses that affects the airways and lungs. The condition develops more intensely than regular flu, leading to severe breathing difficulties that may require mechanical ventilation support. It is characterized by high fever, extreme fatigue, severe muscle aches, and significant respiratory symptoms including chest pain and shortness of breath. The infection can cause inflammation throughout the respiratory system and may lead to complications affecting lung function. In its severe form, the illness can progress to require intensive care unit management.

  • Respiratory Failure

    A condition where the respiratory system cannot maintain adequate gas exchange, resulting in abnormal levels of oxygen and carbon dioxide in the blood. The condition develops when the lungs cannot properly oxygenate blood or remove carbon dioxide from the body. It often requires mechanical ventilation support through intubation to help maintain proper breathing function. The condition can occur as a complication of severe respiratory infections and other serious illnesses affecting lung function.

Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-516058-23-00Protocol codeAPHP210090Estimated enrolment155 patientsSponsorAssistance Publique Hopitaux De Paris

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On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

This service is not affiliated with the European Commission, the EMA, or the official CTIS system. Most information comes from publicly available international clinical-trial registries, supplemented by data from academic sites, national regulators and commercial sponsors. On this site, “treatment” and “therapy” mean a medicine being tested in a clinical trial. Its safety and effectiveness in the use being studied are not yet confirmed, some participants may receive a placebo or a comparator, and taking part does not guarantee a health benefit. The doctor at the research site decides who can take part. This site provides information, not medical advice. Certain content and visual elements on this website have been generated or enhanced using artificial intelligence (AI).