Could common painkillers boost opioid effectiveness for cancer patients?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Inpatient setting (discharge possible, if patient returns for End of Study Visit) * Diagnosis of metastatic or locally advanced cancer * Cancer pain as defined by IASP (International Association for the Study of Pain) * Cancer pain therapy with opioids indicated for pain management or start thereof at baseline (drug, dose, and route at treating physician's discretion) * Average daily pain intensity ≥ 3 on NRS (Numeric Rating Scale) * Ability to swallow oral medication * Informed Consent as documented by signature Exclusion Criteria: * History of allergy or allergy-like symptoms (bronchospasm, urticaria or severe cutaneous adverse reactions (SCARs)) or hypersensitivity to dipyrone (or other pyrazolones or pyrazolidines) or ibuprofen (or other Non-steroidal anti-inflammatory drug incl. acetylsalicylic acid) * Moderate to severe renal insufficiency (creatinine-eGFR (estimated Glomerular Filtration Rate) \<45 ml/min) * Severe heart failure (New York Heart Association class III-IV) * Severe hepatic impairment (liver cirrhosis with ascites) or hepatic porphyria * History of agranulocytosis induced by dipyrone (or other pyrazolones or pyrazolidines) * Active gastric and/or duodenal ulcers or bleeding * History of recurrent gastric and/or duodenal ulcers or gastrointestinal bleeding (≥2 distinct episodes of proven ulceration or bleeding) or increased tendency to bleeding * Third trimester of pregnancy * Breastfeeding * G6PD deficiency * Inflammatory bowel disease (e.g., Crohn's disease, ulcerative colitis) * Intrathecal or epidural opioids or local or regional anesthetic therapy * Additional second opioid for co-analgesic effects or other reasons (e.g., methadone, buprenorphine) * Initiation of therapy with transdermal therapeutic system (TTS) opioid \<48 hours before start of IMP * Use of non-opioids with long half-life (i.e., acemetacin, celecoxib, etodolac, etoricoxib, ketorolac, naproxen, piroxicam, tenoxicam) * Pain unrelated to cancer (e.g. chronic non-cancer pain \[CNCP\], postoperative, particularly following coronary artery or cardiopulmonary bypass surgery) * Inability to follow study procedures or adhere to protocol (e.g., due to language problems, psychological disorders, dementia) * Inability to abstain from other non-opioids (apart from IMP (Investigational Medicinal Product)) during study participation * Participation in any interventional study targeted at pain management * Participant is a family member or employee of the investigator