[Effect of tiaprofenic acid on serum digoxin concentration]

The effect of concomitant tiaprofenic acid (Surgam) administration (200 mg t.i.d.) on serum digoxin concentration (SDC) was evaluated in 12 healthy volunteers on digoxin maintenance treatment. During a 10-day coadministration period with tiaprofenic acid no significant increase in SDC was observed (0.97 +/- 0.24 vs. 1.12 +/- 0.21 ng/ml, p less than 0.05). Mean tiaprofenic acid concentration amounted to 2.85 +/- 1.94 micrograms/ml 14 h after last drug intake. The incidence of adverse reactions was minimal with gastrointestinal upset in one person. Tiaprofenic acid had no influence on red or white blood cell count. Thus, in contrast to various other nonsteroidal antiinflammatory drugs coadministration of tiaprofenic acid (600 mg daily) has no relevant influence on serum digoxin levels.