Diclofenac more effective than acetaminophen in osteoarthritis of the knee

,

Q&A

Diclofenac more effective than acetaminophen in osteoarthritis of the knee

J Fam Pract. 2003 July;52(7):512-525

By

Marc R. Via, MD

BACKGROUND: A small number of studies have compared the effectiveness of acetaminophen with various NSAIDs, with some studies showing equivalence and others showing acetaminophen coming up short. These studies are the basis on which current clinical guidelines recommend acetaminophen over NSAIDs as initial therapy. This study evaluated the effectiveness of acetaminophen (Tylenol) and diclofenac sodium (Voltaren) compared with placebo in adults with osteoarthritis of the knee.
POPULATION STUDIED: The 82 patients in this study were men and women aged 40 to 75 years, recruited from a rheumatology clinic, with unilaterally symptomatic osteoarthritis of the knee. Patients had radiographic evidence of osteoarthritis (Kellgren-Lawrence grade ≥1) and medial compartment involvement.
STUDY DESIGN AND VALIDITY: This research was a randomized, double-blind, placebo-controlled study. Initial allocation to treatment groups was concealed. After a 2-week washout period, patients were randomized to receive treatment with diclofenac (75 mg twice daily), acetaminophen (1000 mg 4 times daily), or matching placebo for 12 weeks. Follow-up visits were scheduled at weeks 2 and 12, at which time pain and function were evaluated. Analysis of data was performed on an intention-to-treat basis.
OUTCOMES MEASURED: The primary outcome was efficacy as measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) at 2 and 12 weeks. This instrument assesses pain, stiffness, and function.
RESULTS: Only patients treated with diclofenac experienced a significant improvement in the primary outcome—the WOMAC—at week 2 (27%; P=.001) and week 12 (25.6%; P=.001) compared with baseline. The individual components (pain, stiffness, and function) of the WOMAC each showed clinical and statistically significant improvement compared with baseline scores at 2 and 12 weeks in the diclofenac-treated group only.

PDF Download

Diclofenac more effective than acetaminophen in osteoarthritis of the knee

Recommended Reading