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Comparing morphine and alfentanil for treating severe acute pain in adults before hospital admission

Verified siteRegistered drugNo placebo
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What is this trial about?

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

This study is looking at severe pain that needs emergency treatment before patients reach the hospital. The two medications being compared are morphine and alfentanil, both of which are strong pain relief medicines given through an injection into a vein. These medications work by blocking pain signals in the body. The purpose of the study is to compare how well these two medicines work at relieving severe sudden pain in adults who are being treated by emergency medical teams before arriving at the hospital.

During the study, patients with severe sudden pain will receive either morphine or alfentanil as their pain treatment. The medical team will measure the pain level using a number scale where patients rate their pain from zero to ten. The main focus is to see how many patients have their pain reduced to a low level within fifteen minutes after receiving the first injection of the assigned medicine. The study will also look at whether patients need additional pain medicine during their emergency care and how long it takes from the first injection until they arrive at the hospital.

The study will also carefully track any unwanted effects that might occur with either medicine. This includes checking breathing rate and oxygen levels, blood pressure, alertness and drowsiness, and whether patients experience nausea, vomiting, or itching. The medical team will monitor all these aspects throughout the emergency care period. The study will also examine whether the type of pain, such as pain from an injury or pain from internal organs, affects how well each medicine works.

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

    Initial treatment administration

    Upon joining the study, you will receive one of two pain relief medications through an intravenous injection (a medication given directly into your vein). The medication will be either morphine or alfentanil, determined by a random selection process.

    If you receive morphine, the medication is called morphine hydrochloride, provided as a solution at a concentration of 10 mg per milliliter.

    If you receive alfentanil, the medication is called alfentanil hydrochloride, provided as a solution at a concentration of 0.5 mg per milliliter.

    Both medications are administered as a single injection into your vein.

  2. Step 2

    Pain assessment at 15 minutes

    Fifteen minutes after receiving the first injection, your pain level will be assessed using a numerical scale from 0 to 10, where 0 means no pain and 10 means the worst pain imaginable.

    You will be asked to rate your current pain level on this scale.

    The goal is to determine if your pain has decreased to a level of 3 out of 10 or lower.

  3. Step 3

    Monitoring for side effects

    Throughout your care, you will be monitored for potential side effects of the pain medication.

    Your breathing rate will be checked to ensure it stays above 12 breaths per minute, and your oxygen saturation (the amount of oxygen in your blood) will be monitored to ensure it stays above 90 percent.

    Your blood pressure will be measured to ensure your systolic pressure (the top number) stays above 80 mmHg.

    Your level of alertness will be observed to ensure you remain awake or only slightly drowsy.

    You will be asked about any nausea (feeling sick to your stomach), vomiting, or itching you may experience.

  4. Step 4

    Additional treatment if needed

    If your pain is not adequately controlled after the first injection, you may receive additional pain relief or sedative medication during your emergency care.

    The type and amount of any additional medication given will be recorded.

  5. Step 5

    Transport to hospital

    You will be transported to the hospital for further care.

    The time between your first pain medication injection and your arrival at the hospital will be recorded.

  6. Step 6

    Pain type classification

    Your pain will be classified as either traumatic pain (caused by an injury) or visceral pain (caused by internal organs).

    Your response to the pain medication will be analyzed based on the type of pain you experienced.

Who can join the trial?

5 criteria

  • You must be 18 years of age or older
  • You must be receiving care from an emergency medical team that is taking part in this study
  • You must have severe acute pain, which means sudden and intense pain that you rate as 6 out of 10 or higher on a pain scale where 0 means no pain and 10 means the worst pain imaginable
  • You must be enrolled in or receiving benefits from a social security scheme, which is a health insurance system
  • You must be able to give your informed consent, meaning you agree to participate after understanding the study, or if the situation is urgent, you can be included first and then give your signed consent later to continue in the study

Who cannot join the trial?

3 criteria

  • The source data does not provide specific exclusion criteria (reasons why patients cannot participate) for this clinical trial
  • Exclusion criteria are conditions or factors that would prevent someone from joining a study to ensure patient safety and reliable results
  • Without detailed exclusion information in the provided data, it is not possible to list specific reasons why a patient would not be able to participate in this pain management study
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Investigated drugs

  • Morphine

    is a strong pain reliever used to treat severe pain. It belongs to a group of medicines called opioids that work by blocking pain signals in the brain and nervous system. In this trial, it is given through an injection into a vein to quickly reduce severe acute pain in emergency situations before patients reach the hospital.

  • Alfentanil

    is a strong pain reliever that also belongs to the opioid group of medicines. It works similarly to morphine by blocking pain signals, but it acts very quickly and for a shorter period of time. In this trial, it is given through an injection into a vein to quickly reduce severe acute pain in emergency situations before patients reach the hospital.

What is already known about the treatment

  • Morphine

    Morphine is a strong pain medication given by injection into a vein, muscle, or under the skin, and it is widely recognized as one of the most effective treatments for severe pain in emergency and hospital settings. This medication works by attaching to specific receptors in the brain and spinal cord called opioid receptors, which blocks pain signals from reaching the brain and changes how the body perceives and responds to pain. Morphine belongs to a class of drugs called opioid analgesics and is primarily used to treat moderate to severe pain, including pain from injuries, surgeries, and serious medical conditions. It is considered a standard treatment option in emergency medicine and is included on the World Health Organization's list of essential medicines.

  • Alfentanil

    Alfentanil is a potent pain-relieving medication administered through injection into a vein, commonly used in emergency situations and during medical procedures to quickly control severe pain. This drug works by binding to opioid receptors in the central nervous system, which interrupts the transmission of pain signals and produces rapid pain relief that typically begins within one to two minutes of administration. Alfentanil is classified as an opioid analgesic and is particularly valued in emergency medicine for its fast onset and shorter duration of action compared to other similar medications. It is primarily indicated for the management of acute severe pain and is often used by emergency medical services in pre-hospital care settings.

Investigated diseases

Severe Pain – Severe pain is an intense and distressing physical sensation that significantly affects a person's daily functioning and quality of life. It is typically rated as 6 or higher on a pain scale of 0 to 10, where 10 represents the worst imaginable pain. This condition can arise from various causes, including injuries, surgical procedures, or internal organ problems. Severe pain can be classified as either traumatic, resulting from physical injury to the body, or visceral, originating from internal organs. The sensation occurs when pain receptors in the body send strong signals through nerves to the brain. Without proper management, severe pain can lead to increased stress, difficulty breathing, elevated heart rate, and reduced ability to perform normal activities.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-522817-50-00Protocol code22_RIPH1-08Estimated enrolment242 patientsSponsorCHU De Martinique

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