Multicenter, double-blind, clinical trial comparing two tablets bid to onetablet qid of the same acetaminophen-dextropropoxyphen-caffeine combination in patients with osteoarthritis.

The optimal dosing schedule for the acetaminophen-dextropropoxyphen-caffein e combination remains unclear, The efficacy and safety of this combination given as two tablets bid or one tablet qid were compared in a double-blind study in 627 patients with pain due to spinal or lower limb osteoarthritis, Eight patients received a placebo, Efficacy was evaluated in those patient s whose visual analog scale (VAS) pain score was greater than 40 mm, In eac h patient, the VAS pain score was determined on nine occasions within 24 ho urs of treatment initiation; the primary efficacy criterion was the sum of pain severity differences (SPSD) calculated as the sum of the differences b etween the first (baseline) score and each of the eight subsequent scores, Clinical safety was evaluated based on the number of adverse experiences re ported by the patients and on a specific sleep questionnaire. The SPSD was 116 mm in the one tablet qid group, 118 mm in the two tablets bid group, an d 85 mm in the placebo Stoup. No significant differences were found between the two active drug dosing schedules. Conversely, significant differences (P=0.03) in favor of the active drug were demonstrated between each of the two dosing schedules and the placebo. There were no Significant sleep quali ty differences between the two active drug dosing schedules or between eith er of these schedules and the placebo. As compared to qid administration, t wice-daily administration of the acetaminophen-dextropropoxyphen-caffeine i n the same total daily dosage does not seem to significantly affect efficac y sleep quality, or overall safety in osteoarthritis patients.