PT - JOURNAL ARTICLE AU - Michael Doherty AU - Chris Hawkey AU - Michael Goulder AU - Iain Gibb AU - Nicola Hill AU - Sue Aspley AU - Sandie Reader TI - A randomised controlled trial of ibuprofen, paracetamol or a combination tablet of ibuprofen/paracetamol in community-derived people with knee pain AID - 10.1136/ard.2011.154047 DP - 2011 Sep 01 TA - Annals of the Rheumatic Diseases PG - 1534--1541 VI - 70 IP - 9 4099 - http://ard.bmj.com/content/70/9/1534.short 4100 - http://ard.bmj.com/content/70/9/1534.full SO - Ann Rheum Dis2011 Sep 01; 70 AB - Objectives To compare the efficacy and safety of single versus combination non-prescription oral analgesics in community-derived people aged 40 years and older with chronic knee pain. Methods A randomised, double-blind, four-arm, parallel-group, active controlled trial investigating short-term (day 10) and long-term (week 13) benefits and side-effects of four regimens, each taken three times a day: ibuprofen (400 mg); paracetamol (1000 mg); one fixed-dose combination tablet (ibuprofen 200 mg/paracetamol 500 mg); two fixed-dose combination tablets (ibuprofen 400 mg/paracetamol 1000 mg). Results There were 892 participants (mean age 60.6, range 40–84 years); 63% had radiographic knee osteoarthritis and 85% fulfilled American College of Rheumatology criteria for osteoarthritis. At day 10, two combination tablets were superior to paracetamol (p<0.01) for pain relief (determined by mean change from baseline in WOMAC pain; n=786). At 13 weeks, significantly more participants taking one or two combination tablets rated their treatment as excellent/good compared with paracetamol (p=0.015, p=0.0002, respectively; n=615). The frequency of adverse events was comparable between groups. However, by 13 weeks, decreases in haemoglobin (≥1 g/dl) were observed in some participants in all groups. Twice as many participants taking two combination tablets had this decrease compared with those on monotherapy (p<0.001; paracetamol, 20.3%; ibuprofen, 19.6%; one or two combination tablets, 24.1%, 38.4%, respectively). Conclusions Ibuprofen/paracetamol combination analgesia, at non-prescription doses, confers modest short-term benefits for knee pain/osteoarthritis. However, in this population, paracetamol 3 g/day may cause similar degrees of blood loss as ibuprofen 1200 mg/day, and the combination of the two appears to be additive. Study no ISRCTN77199439