AMSTERDAM — For pain associated with knee osteoarthritis, extended-release acetaminophen is a possible alternative to cyclooxygenase-2 inhibitors, Dr. Thomas J. Schnitzer reported at the annual European Congress of Rheumatology.
Current osteoarthritis (OA) guidelines recommend the original shorter-acting formulation of acetaminophen at 4 g/day as a first-line treatment for pain associated with the disease. The extended-release formulation, which is commercially available, offers the advantage of less frequent dosing, explained Dr. Schnitzer, professor of medicine at Northwestern University, Chicago.
He reported on a 4-week, 23-center, double-blind U.S. clinical trial of 403 adults with knee OA. Participants were randomized to extended-release acetaminophen at the recommended adult dosage of 1,300 mg t.i.d., rofecoxib at 12.5 mg/day, or rofecoxib at 25 mg/day.
The mean 143.5-mm drop on the 0- to 500-mm visual analog scale in the acetaminophen group was not significantly different from the results with rofecoxib at 12.5 mg/day, but it was inferior to the 175.9-mm drop with high-dose rofecoxib.
Study withdrawal rates for lack of efficacy were 1.5% with extended-release acetaminophen and 3.6% and 1.6%, respectively, for low- and high-dose rofecoxib. Dropout due to adverse events occurred in 5.9% of the acetaminophen group, 6.5% with rofecoxib 12.5 mg, and 7.0% with 25 mg. Headache was reported by 6.6% of patients on extended-release acetaminophen, vs. 0.7% on the low dose and 5.4% on the high dose of rofecoxib, Dr. Schnitzer noted. Two patients had an acute MI during the 4-week study, both in the rofecoxib 12.5-mg arm. Investigators deemed the MIs unrelated to the study medication.
The study was sponsored by McNeil Consumer Healthcare.