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Evidence summaries

Paracetamol for Osteoarthritis

Paracetamol is more effective than placebo but less effective than NSAIDs for rest pain and overall pain in osteoarthritis. Level of evidence: "A"

A Cochrane review [Abstract] 1 included 15 studies with a total of 5 986 subjects. Acetaminophen (paracetamol) was superior to placebo in five of the seven RCTs and had a similar safety profile. A pooled analysis of five trials of overall pain using multiple methods demonstrated a statistically significant reduction in pain (SMD -0.13, 95% CI -0.22 to -0.04), which is of questionable clinical significance. The relative percent improvement from baseline was 5% with an absolute change of 4 points on a 0 to 100 scale. The NNT to achieve an improvement in pain ranged from 4 to 16. In the comparator-controlled RCTs, acetaminophen was less effective overall than NSAIDs in terms of pain reduction, global assessments and in terms of improvements in functional status. For pain in motion the difference was not statistically or clinically significant. Patients taking traditional NSAIDs were more likely to experience an adverse GI event (RR 1.47, (95% CI 1.08 to 2.00).

Another systematic review 2 included 5 RCTs with a total of 655 subjects. NSAIDs evaluated (1 RCT each) included diclofenac (150 mg/d), naproxen (750 mg/d), ibuprofen (2400 or 1200 mg/d), ketoprofen (200 mg/d), and fenoprofen (600 mg/d). Dosage of paracetamol varied from 990 to 6 000 mg/day. Pooled standardized mean difference for general pain was 0.33 (95% CI 0.15 to 0.51; 3 trials [naproxen, ibuprofen, diclofenac], n=589), indicating a small effect in favour of NSAID. Pooled estimates for other outcome measures like functional disability or pain on motion were smaller.

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    References

    • Towheed TE, Maxwell L, Judd MG, Catton M, Hochberg MC, Wells G. Acetaminophen for osteoarthritis. Cochrane Database Syst Rev 2006 Jan 25;(1):CD004257. [PubMed]
    • Wegman A, van der Windt D, van Tulder M, Stalman W, de Vries T. Nonsteroidal antiinflammatory drugs or acetaminophen for osteoarthritis of the hip or knee? A systematic review of evidence and guidelines. J Rheumatol 2004 Feb;31(2):344-54. [PubMed]

Primary/Secondary Keywords