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Study on Paracetamol and Strong Opioids for Pain Relief in Patients with Metastatic Cancer

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 withdrawing paracetamol when used alongside strong opioids for managing pain related to metastatic cancer. Metastatic cancer is a type of cancer that has spread from its original site to other parts of the body. The trial aims to determine if stopping paracetamol affects pain control compared to continuing its use with opioids, which are strong pain-relieving medications.

Participants in the study will either continue taking paracetamol or switch to a placebo while still receiving their regular opioid treatment. The study will observe how this change impacts their pain levels and any side effects related to opioid use. The trial will last for a short period, and participants will take the medications in tablet form.

The main goal is to see if stopping paracetamol leads to worse pain control compared to keeping it in the treatment plan. This information will help doctors understand the best way to manage pain for patients with metastatic cancer who are already using strong opioids.

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

    Joining the study

    Upon joining the study, you will be randomly assigned to one of two groups. This process is called randomization and ensures that each participant has an equal chance of receiving either the paracetamol or the placebo.

    You will continue to receive your regular strong opioids for cancer pain throughout the study.

  2. Step 2

    Medication administration

    If you are assigned to the paracetamol group, you will take 1 gram of paracetamol in tablet form, three or four times a day, as you have been doing for at least the past five days.

    If you are assigned to the placebo group, you will take a placebo tablet, which looks like the paracetamol tablet but does not contain any active medication, three or four times a day.

  3. Step 3

    Monitoring and reporting

    Throughout the trial, you will be asked to report your average pain intensity. This will help assess the effectiveness of the treatment you are receiving.

    You will also be asked to report any side effects you experience that may be related to the opioids you are taking.

  4. Step 4

    Completion of the trial

    The trial will continue until the estimated end date of December 31, 2027, unless otherwise specified by the study team.

    At the end of the trial, your opioid consumption will be evaluated, including both scheduled and on-demand use.

Who can join the trial?

10 criteria

  • Participant must be 18 years of age or older at the time of signing the informed consent.
  • Able to take the study drug or placebo in the form of tablets.
  • Capable of giving signed informed consent, which means you understand the study and agree to participate.
  • Participants should be under palliative care or reviewed by an oncology service. Palliative care is specialized medical care focused on providing relief from the symptoms and stress of a serious illness.
  • Diagnosis of metastatic cancer. This includes all incurable solid tumors in an advanced stage, either locally advanced or spread to other parts of the body. It also includes certain types of blood cancer in a palliative setting.
  • Clinician-predicted life expectancy of more than 2 months.
  • Receiving daily regular strong opioids for cancer pain. Strong opioids are powerful pain-relieving medications.
  • Receiving a stable scheduled opioid dose for the last 48 hours.
  • Receiving paracetamol (a common pain reliever) 1 gram three or four times a day for at least five days.
  • Average pain intensity in the past 24 hours should be between 2 and 7 on a scale from 0 to 10, where 0 means no pain and 10 means the worst pain possible.

Who cannot join the trial?

1 criterion

  • Patients with **metastatic cancer disease** cannot participate. This means the cancer has spread to other parts of the body.
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Investigated drugs

  • Paracetamol

    is a common pain reliever and fever reducer. In this trial, it is being tested to see if stopping its use affects pain control in patients who are also taking strong opioids for cancer-related pain. The study aims to find out if continuing to use paracetamol with opioids provides better pain relief than stopping paracetamol.

  • Strong Opioids

    are powerful pain medications used to manage severe pain, often related to cancer. They work by binding to specific receptors in the brain to reduce the perception of pain. In this trial, strong opioids are used in combination with paracetamol to assess their effectiveness in controlling pain when paracetamol is withdrawn.

What is already known about the treatment

Paracetamol – Paracetamol is typically administered orally in tablet form, but it can also be given as a liquid or intravenously. It is widely used in medicine for its pain-relieving and fever-reducing properties. In the context of this clinical trial, it is being studied for its effectiveness in managing moderate to severe cancer-related pain when used alongside strong opioids. Paracetamol works by inhibiting certain enzymes in the brain that produce pain and fever signals. It is classified as an analgesic and antipyretic medication.

Investigated diseases

Metastatic Cancer – Metastatic cancer occurs when cancer cells spread from the primary site to other parts of the body. This process involves cancer cells breaking away from the original tumor, traveling through the bloodstream or lymphatic system, and forming new tumors in other organs or tissues. The progression of metastatic cancer can vary depending on the type of primary cancer and the organs affected. Common sites for metastasis include bones, liver, lungs, and brain. As the disease progresses, it can lead to a range of symptoms depending on the location and size of the metastatic tumors. The spread of cancer cells can disrupt the normal function of affected organs, leading to further complications.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-515012-53-00Protocol codePARASTOPEstimated enrolment204 patientsSponsorOslo University Hospital HF

sourced from the EU Clinical Trials Register and site verification

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