PARASTOP - Paracetamol With Strong Opioids

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