Indomethacin in rheumatoid arthritis: comparison of oral and rectal dosing.

1 Indomethacin 100 mg nightly for 1 week has been administered to 13 patients with rheumatoid arthritis by both oral and rectal routes in a double-blind, randomized, cross-over study. 2 Clinical assessments were performed at 09.00 and 14.00 h on the last 3 days of each active treatment period and compared to the results on the last 2 days of the placebo control period. 3 Indomethacin produced significant improvements in the clinical assessments at both 09.00 and 14.00 h compared to placebo but not differences were seen between the two routes of administration. 4 No significant difference was seen in the side effects experienced in the two periods. 5 The mean (+/- s.e. mean) plasma indomethacin concentration at 09.00 h in the oral period was 200.3 +/- 27.4 ng/ml, not significantly different from that in the suppository period (220.0 +/- 28.9 ng/ml). 6 Indomethacin 100 mg nightly by mouth is as effective as a 100 mg suppository and easier to administer.