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Study Comparing Intramuscular and Intranasal Naloxone for Reversing Opioid Overdose in Healthy Volunteers

Fast replyRegistered drugNo placebo
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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 studying the effects of different forms of naloxone in reversing opioid toxicity. Opioid toxicity occurs when someone has taken too much of an opioid, which can lead to dangerous symptoms like difficulty breathing. The study will compare the effectiveness of naloxone given as an injection into the muscle (intramuscular) and as a nasal spray (intranasal) in healthy volunteers. The main goal is to determine how many doses are needed to help restore normal breathing in individuals who have been affected by opioids.

The medications being studied include ZIMHI™ (naloxone hydrochloride injection) for intramuscular use, NARCAN® (naloxone hydrochloride) nasal spray, and Naloxone 400 micrograms/ml solution for injection/infusion. Additionally, Fentanyl, a powerful opioid, is also part of the study to understand its interaction with naloxone. The study will involve administering these medications to participants and observing their effects on breathing and other bodily functions.

Participants will receive multiple doses of either the intramuscular or intranasal form of naloxone, and researchers will monitor how quickly and effectively each form works to reverse the effects of opioids. The study will also measure various factors such as the concentration of naloxone and fentanyl in the blood, as well as changes in pupil size and muscle tone. This research aims to provide valuable insights into the best ways to treat opioid overdoses and improve patient outcomes.

The research process

The trial runs in 4 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment

    Upon joining the study, an initial assessment will be conducted. This includes a review of your medical and surgical history, a physical examination, and tests such as vital signs, a 12-lead ECG (a test that records the electrical activity of the heart), hematology (blood tests), and blood chemistry.

  2. Step 2

    Medication administration

    You will receive multiple doses of naloxone, which is a medication used to reverse opioid effects. The administration will be either through an intramuscular injection (injected into a muscle) or an intranasal spray (sprayed into the nose).

    The goal is to determine how many doses are needed to restore normal breathing levels.

  3. Step 3

    Monitoring

    Throughout the trial, your breathing, blood levels of naloxone and fentanyl, pupil size, and muscle tone will be monitored. This is to ensure your safety and to gather data on how the medication is working.

  4. Step 4

    Follow-up

    After the administration and monitoring phases, there will be a follow-up to assess your overall health and any effects of the medication. This may include additional tests similar to those conducted during the initial assessment.

Who can join the trial?

6 criteria

  • Participants must be healthy volunteers.
  • Participants must be between 18 and 65 years old.
  • Participants must have a body mass index (BMI) between 19 and 40 kg/m2. BMI is a measure of body fat based on height and weight.
  • Participants must be opioid users who use opioids at daily doses of 60 mg or more in terms of oral morphine equivalents. There is no upper limit for opioid use.
  • Participants who use opioids must be stable. Stability is determined by the study doctor based on a medical evaluation, which includes checking the participant's medical and surgical history, physical examination, vital signs, heart test (12-lead ECG), blood cell counts (hematology), and blood chemistry.
  • Both male and female participants are eligible.

Who cannot join the trial?

3 criteria

  • Participants must be healthy volunteers. This means you should not have any ongoing medical conditions.
  • Participants must be within a specific age range. Please ensure you meet the age requirements for the study.
  • Both male and female participants are eligible, but you must not be part of a vulnerable population. This means you should not be in a group that needs special protection or care.
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Investigated drugs

Naloxone is a medication used to quickly reverse the effects of opioid overdose. It works by blocking the effects of opioids on the brain, which can help restore normal breathing in someone who has overdosed. In this clinical trial, naloxone is being tested in two different forms: intramuscular (injected into a muscle) and intranasal (sprayed into the nose). The goal is to see how many doses are needed to help people start breathing normally again after an opioid overdose. This study is important because it could help determine the most effective way to use naloxone in emergency situations.

What is already known about the treatment

Naloxone – Naloxone is a medication administered either through an injection into the muscle (intramuscular) or as a spray into the nose (intranasal) to quickly reverse the effects of opioid overdose. It is well-established in medical practice and literature as a life-saving treatment for opioid toxicity. The primary use of naloxone is to restore normal breathing in individuals who have overdosed on opioids. At the molecular level, naloxone works by attaching to opioid receptors in the brain, blocking the effects of opioids like heroin or prescription painkillers. It is classified as an opioid antagonist, meaning it counteracts the effects of opioids.

Investigated diseases

Healthy volunteers – This term refers to individuals who do not have any known medical conditions or diseases. They are often used in clinical trials to establish baseline data or to test the effects of new treatments or medications. In the context of a study, healthy volunteers help researchers understand how a drug or treatment affects a typical, healthy human body. They do not exhibit symptoms of the disease being studied, as they are not affected by it. Their participation is crucial for comparing results with those of individuals who have the condition being researched. Healthy volunteers provide a control group to ensure that the effects observed in the study are due to the treatment and not other variables.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2023-505338-93-00Estimated enrolment22 patientsSponsorLeids Universitair Medisch Centrum (LUMC)

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