Acetaminophen (paracetamol) improves pain and well-being in people with advanced cancer already receiving a strong opioid regimen: a randomized, double-blind, placebo-controlled cross-over trial.

PURPOSE: To determine whether adding regular acetaminophen (paracetamol) could improve pain and well-being in people with advanced cancer and pain despite strong opioids. PATIENTS AND METHODS: Participants took acetaminophen for 48 hours and placebo for 48 hours. The order (acetaminophen or placebo first) was randomly allocated. Pain was the primary outcome. Preferences, number of opioid breakthrough doses, overall well-being, nausea and vomiting, drowsiness, constipation, and cold sweats were secondary outcomes. Patients rated themselves daily with visual analog scales (VAS) and a verbal numeric scale (VNS) for pain, all scaled from 0 to 10. RESULTS: Thirty patients completed the trial. The oral opioid was morphine in 23 patients and hydromorphone in seven patients. The median daily opioid dose in oral morphine equivalents was 200 mg (range, 20 to 2,100 mg). Nonsteroidal anti-inflammatory drugs, corticosteroids, or both were used by 16 patients. Pain and overall well-being were better for patients receiving acetaminophen than for those receiving placebo. The mean difference was 0.4 (95% CI, 0.1 to 0.8; P =.03) in VNS for pain, 0.6 (95% CI, -0.1 to 1.3; P =.09) in VAS for pain, and 0.7 (95% CI, 0.0 to 1.4; P =.05) in VAS for overall well-being. More patients preferred the period they took acetaminophen (n = 14) than the period they took placebo (n = 8), but many had no preference (n = 8). There were no differences in the other outcomes. CONCLUSION: Acetaminophen improved pain and well-being without major side effects in patients with cancer and persistent pain despite a strong opioid regimen. Its addition is worth considering in all such patients.