Digoxin: use pattern in Estonia and bioavailability of the local market leader.

Author(s): Pahkla R, Irs A, Oselin K, Rootslane L

Affiliation(s): Department of Pharmacoogy, University of Tartu, Estonia.

Publication date & source: 1999-10, J Clin Pharm Ther., 24(5):375-80.

Publication type: Clinical Trial; Randomized Controlled Trial

BACKGROUND: In comparison with neighbouring Scandinavian countries, the use of digoxin in Estonia is high. The present study was carried out to determine the use pattern of digoxin in Estonia and bioavailability of the local market leader preparation in comparison with Lanoxin. METHOD: Drug use data were evaluated from the annual reports of wholesale companies. For the bioequivalence study, a single-blind cross-over randomised two-way single-dose comparative bioavailability study was performed using 14 healthy volunteers. Digoxin concentrations in serum samples and urine were measured by chemiluminescent competitive immunoassay. RESULTS: The use of digoxin in Estonia has increased by 35% during the period 1994-97. The steady market leader was the local generic drug. No statistically significant differences were found in any pharmacokinetic parameter between the generic preparation and Lanoxin. All parameters showed considerable variability. The total amount of drug excreted was the parameter with lowest inter- individual variation. CONCLUSION: The present study indicates that the generic digoxin preparation studied is bioequivalent to Lanoxin. The increasing use of digoxin in Estonia is not caused by low bioavailability of the local market leader but by therapeutic traditions.