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Study on the Effects of Acetylcysteine and Naloxone on Opioid-Induced Breathing Problems in Healthy Individuals

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What is this trial about?

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

This clinical trial is focused on understanding how certain medications affect breathing. The study involves healthy individuals and examines the effects of a pain medication called fentanyl, which is known to sometimes cause breathing difficulties, a condition known as opioid-induced respiratory depression. The trial also investigates the use of another medication, acetylcysteine (also referred to as L-NAC), which is being tested to see if it can help improve breathing when fentanyl is used.

Participants in the study will receive these medications through an intravenous infusion, which means the drugs are delivered directly into the bloodstream through a vein. The study will also use a placebo for comparison. The main goal is to see if acetylcysteine can help reverse the breathing problems caused by fentanyl. Additionally, the study will monitor various aspects of breathing, such as how much air is inhaled and exhaled in a minute, the levels of carbon dioxide in the breath, and other related measures.

The trial will take place over a short period, with participants receiving the treatments and being closely monitored for any changes in their breathing patterns. The study aims to provide valuable insights into how these medications interact and whether acetylcysteine can be an effective treatment for breathing issues caused by opioid medications like fentanyl.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the study

    Upon joining the study, you will be informed about the trial's purpose and procedures. You will need to confirm your understanding and agreement to participate by signing a consent form.

  2. Step 2

    Initial assessment

    You will undergo an initial assessment to ensure you meet the study's criteria. This includes checking your age, body mass index (BMI), and ability to understand the study information.

  3. Step 3

    Administration of <b>fentanyl</b>

    You will receive an intravenous infusion of fentanyl, a painkiller, to induce a controlled state of reduced breathing activity. This is part of the study to understand its effects on breathing.

  4. Step 4

    Administration of <b>L-NAC</b>

    Following the fentanyl infusion, you will receive an intravenous infusion of L-NAC (acetylcysteine). This is to investigate its ability to reverse the breathing reduction caused by fentanyl.

  5. Step 5

    Monitoring and data collection

    Your breathing will be closely monitored throughout the study. This includes measuring your minute ventilation, which is the amount of air you breathe in one minute.

    Additional measurements will include the carbon dioxide levels in your breath, your breathing rate, and the volume of each breath. Blood samples will be taken to analyze gas levels and the concentrations of fentanyl and L-NAC in your blood.

  6. Step 6

    Completion of the study

    Once all necessary data is collected, your participation in the study will be complete. You will be informed about any follow-up procedures or additional information related to the study's findings.

Who can join the trial?

4 criteria

  • Must be between the ages of 18 and 40 years old.
  • Must have a Body Mass Index (BMI) between 19 and 30 kg/m2. BMI is a measure that uses your height and weight to work out if your weight is healthy.
  • Must be able to read and understand the information provided about the study.
  • Must be a healthy individual with no medical conditions.

Who cannot join the trial?

10 criteria

  • Participants must be healthy with no medical conditions.
  • Participants should not have any respiratory issues or breathing problems.
  • Participants must not be taking any opioid medications regularly. Opioids are strong painkillers.
  • Participants should not have any known allergies to fentanyl or similar medications. Fentanyl is a type of opioid.
  • Participants must not be pregnant or breastfeeding.
  • Participants should not have a history of substance abuse or addiction.
  • Participants must not have participated in another clinical trial recently.
  • Participants should not have any significant heart conditions or heart disease.
  • Participants must not have any liver or kidney problems.
  • Participants should not have any mental health disorders that are not well controlled.
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Investigated drugs

  • L-NAC

    is a medication being studied for its potential to help reverse breathing problems caused by opioids. Opioids, like fentanyl, can slow down breathing, which can be dangerous. L-NAC is given through an IV, which means it goes directly into the bloodstream. The goal of using L-NAC in this study is to see if it can help improve breathing in people who have taken opioids.

  • Fentanyl

    is a powerful opioid pain medication. It is often used to treat severe pain, such as pain after surgery or pain from cancer. However, one of the side effects of fentanyl is that it can slow down breathing, which can be very serious. In this study, fentanyl is used to see how well L-NAC can help with the breathing problems that fentanyl can cause.

What is already known about the treatment

L-NAC – L-NAC is administered through an intravenous infusion, meaning it is delivered directly into the bloodstream through a vein. Currently, L-NAC is being studied in clinical trials to understand its effects on reversing breathing problems caused by opioids, specifically fentanyl. The main therapeutic indication for L-NAC in this trial is to help healthy individuals who have been given fentanyl to see if it can counteract the breathing issues that opioids can cause. At the molecular level, L-NAC works by potentially affecting certain pathways in the body that are involved in breathing regulation, although the exact mechanism is still under investigation. It is classified pharmacologically as an antioxidant and mucolytic agent, which means it can help reduce oxidative stress and thin mucus, but its role in this trial is focused on respiratory effects.

Investigated diseases

Opioid-Induced Respiratory Depression – This condition occurs when opioids, such as fentanyl, suppress the body's ability to breathe effectively. It is characterized by a decrease in the rate and depth of breathing, leading to reduced oxygen intake and increased carbon dioxide levels in the blood. The progression involves a gradual slowing of respiratory rate and a decrease in tidal volume, which is the amount of air moved in and out of the lungs with each breath. As the condition advances, there may be a noticeable reduction in minute ventilation, which is the total volume of air inhaled and exhaled per minute. This can result in elevated end-tidal carbon dioxide levels, indicating impaired gas exchange. If not addressed, the condition can lead to significant respiratory compromise.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase ITrial ID2023-503912-34-00Estimated enrolment18 patientsSponsorLeids Universitair Medisch Centrum (LUMC)

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