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NCT Number: NCT05051735

PARASTOP - Paracetamol With Strong Opioids

Current guidelines recommend all people with cancer-related pain should be prescribed paracetamol, even those receiving high doses of strong pain killers (opioids) such as morphine. Although this has been shown in studies to be beneficial in other conditions, for instance dental work and after surgery, it has not been shown to further improve pain in people with cancer-related pain. Taking tablets is burdensome to patients and the study aims to determine whether the inconvenience of taking eight extra paracetamol tablets per day can be justified.

The study plans to show whether or not pain control is changed (non-inferior) when stopping paracetamol compared to continued use of paracetamol in people already taking strong pain killers for cancer-related pain. Voluntary participants who are taking a combination of paracetamol and a strong opioid are recruited to the study.

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Key information

Conditions

Cancer Pain Cancer Neoplasms Neurologic Manifestations Pain Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Participants must be ≥ 18 years of age inclusive, at the time of signing the informed consent.
  • ≥50 kg (due to paracetamol dosage)
  • Participants who are under palliative care or oncology service review
  • Diagnosis of metastatic cancer
  • Clinician-predicted life expectancy >2 months
  • Receiving daily regular strong opioids for cancer pain
  • Receiving stable scheduled opioid dose last 48 hours*
  • Receiving paracetamol 1 gram x three or four times a day for at least five days
  • Average pain intensity past 24 hours ≥ 2 and ≤ 7 (NRS 0-10)*
  • Able to take study drug/placebo as tablets
  • Able to comply with all study procedures
  • Capable of giving signed informed consent as described in Appendix 1 which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in this protocol.
  • It is allowed to repeat procedure within the screening period without considering the participant being a rescreen

Exclusion criteria

  • History of allergy or hypersensitivity to any of the active substances or excipients in the study drug
  • Known severe liver or renal failure equivalent with CTCAE Grade 3 or 4* precluding continuation of paracetamol. (*Common Terminology Criteria for Adverse Events (CTCAE) Version 5.0)
  • Participants receiving subcutaneous, intravenous, intrathecal, or epidural opioid therapy
  • Participants receiving systemic anticancer treatment during the intervention period if they are anticipated to have increasing pain or other symptoms related to the treatment
  • Co-enrolment in other drug trials. Participants will not be enrolled in any other on-going interventional clinical trial. Study participants may be enrolled in non-interventional research (e.g. questionnaire, tissue collection studies)
  • Previously enrolled in this study
  • Pregnant or lactating women

Treatment and study plan

Paracetamol

Drug

Paracetamol 500 mg

Other names: Acetaminophen

Placebo

Drug

Placebo

Primary outcomes

  1. To establish whether placebo with strong opioids compared to paracetamol together with strong opioids provides non-inferior analgesia for cancer-related pain.

    Time frame: 7 days

    Numeric Rating Scale 0-10: Average pain intensity past 24 hours

Secondary outcomes

  1. To establish whether placebo with strong opioids compared to paracetamol with strong opioids changes opioid related side effects.

    Time frame: 7 days

    Opioid Side Effects Questionnaire

  2. To establish whether placebo with strong opioids compared to paracetamol with strong opioids changes global rating of improvement.

    Time frame: 7 days

    Patient Global Impression of Change

  3. To establish whether placebo with strong opioids compared to paracetamol with strong opioids changes opioid requirements.

    Time frame: 7 days

    Opioid consumption

Sponsors and collaborators

Lead sponsor

Oslo University Hospital

Other

Collaborators

  • Sykehuset Telemark

Registry information

Official study title

PARASTOP - Paracetamol With Strong Opioids. A Randomized, Double-blind, Parallel-group Non-inferiority Phase III Withdrawal Trial of Paracetamol Versus Placebo in Conjunction With Opioids for Moderate to Severe Cancer-related Pain

Acronym: PARASTOP

Important dates

Study start
2021
Primary completion
2026
Study completion
2026
First posted
Sep 21, 2021
Registry last updated
Feb 25, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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