Indomethacin: effects on cold-induced pain and the nervous system in healthy volunteers

The sensitivity of the cold-induced pain (CP) model to the non-steroidal anti-inflammatory drug (NSAID) indomethacin was studied in healthy volunteers. Effects on the central nervous system were also sought. Subjects received single oral doses of indomethacin 50 and 100 mg, dipipanone 8 mg and placebo, according to a double-blind, randomised, balanced, cross-over design with an interval of 7 days between occasions. A test battery was performed before each treatment and then at 45, 105 and 165 min post treatment. Pain scores were unaltered by indomethacin at either dose, but the drug certainly affected the CNS, increasing respiratory drive and changing self-assessed mood. It is concluded that the CP model is insensitive to indomethacin, even in doses which have clear-cut CNS effects. The respiratory stimulant action of indomethacin may deserve further study.