Comparison of Gastrointestinal Blood Loss in Healthy Male Volunteers During Repeated Administration of Standard and Sustained Action Tiaprofenic Acid and Sustained Release Indomethacin
Gastrointestinal blood loss was measured in 30 healthy male volunteers before and during 4 weeks of oral treatment with either tiaprofenic acid tablets 300mg twice daily, tiaprofenic acid sustained action (SA) capsules 600mg once daily, or indomethacin sustained release (SR) capsules 75mg once daily, in an open parallel-group study of 38 days’ duration. Autologous erythrocytes labelled with 51Cr were given intravenously on the first study day. Gastrointestinal blood loss was measured by comparing faecal and red blood cell 5lCr activity during the second and fourth weeks of drug treatment. Blood loss was significantly greater during treatment with all 3 active preparations than during the pretreatment period, but this comparison is of limited value because placebo was not given in parallel and because in 4 subjects, who had to have their erythrocytes relabelled, there was no pretreatment data. The tiaprofenic acid SA group had consistently lower blood loss than the tiaprofenic acid tablet group. Both these groups also had consistently lower blood loss than the indomethacin SR group, although the difference between the treatment groups was not significant. Blood loss during the fourth week of treatment was less than during the second week of treatment for both the tiaprofenic acid SA and indomethacin SR capsule groups. With tiaprofenic acid tablets, blood loss was very similar at weeks 2 and 4 but this result should be viewed with caution because data at week 2 were missing for 3 subjects. Thus, formulation of tiaprofenic acid as a sustained action capsule does not appear to increase gastric irritancy as measured by faecal blood loss.