Abstract

The analgesic efficacy of 200 mg ibuprofen plus 30 mg codeine, 200 mg ibuprofen and placebo was investigated in a new analgesic evaluation model using single- and repeated-dose administration. The study was a double-blind randomized cross-over investigation in 26 coxarthrosis patients with persistent pain. After a washout period of at least 2 days with paracetamol available as rescue analgesic, each of the 3 treatments was administered in a total of 6 doses during 24 h. The hourly pain intensity was recorded on a 100-mm visual analogue scale (VAS) for 8 h after the 1st and the 6th dose. The pretreatment VAS score was 31-37 mm. After the 1st dose the 8-h mean pain intensity values were 25, 27, and 26 mm after ibuprofen plus codeine, ibuprofen, and placebo, respectively. Following another 5 doses every 4 h the corresponding values were 10, 17 and 29 mm. Repeated administration of both active drugs reduced the pain intensity significantly. The analgesic efficacy of ibuprofen plus codeine was significantly superior to that of ibuprofen which was, in turn, superior to that of placebo. In conclusion, analgesic efficacy was better differentiated after repeated-dose than after single-dose administration. The present study design was able to differentiate between 200 mg ibuprofen plus 30 mg codeine and 200 mg ibuprofen alone in a relatively small number of patients.