OBJECTIVE Does the addition of 600 mg rifampicin or 50 mg methotrexate improve pain relief after injection of the rheumatoid knee with 20 mg triamcinolone hexacetonide (TH)? METHODS Eighty-two patients on stable therapy were allocated at random to receive intra-articular TH alone, TH and methotrexate (TH+M) or TH and rifampicin (TH+R). Pain was recorded by a weekly chart and analysed using the area under the curve (AUC), periods of total pain relief and duration of effect. Examinations and microwave thermography were performed by an independent meteorologist at baseline, 3 and 6 months. RESULTS Using the AUC, pain was significantly better in the TH+R group compared with TH alone (P=0.039, Mann Whitney U). The median duration of improved pain scores was 13.5 weeks with TH alone, 10 with TH+M and 19 with TH+R. Examination and microwave thermography revealed improvements compared with baseline, but there were no significant differences between the groups. Eleven of 28 patients treated with TH + R developed a flare of post-injection pain. CONCLUSIONS Whilst the addition of rifampicin improved pain relief, the occurrence of pain after injection remains a problem. Measures to minimize this are needed when TH+R is used.