Monitoring of tinzaparin treatment at treatment dose of 10 days in elderlypatients

Purpose. - Renal impairment, which is frequently observed in eldery patient s, raises the question of low molecular weight heparins treatment dose adju stment in this population. Thus, we conducted a prospective study to determ ine whether tinzaparin, administered subcutaneously at treatment dose (175 anti-Xa IU/kg) once daily for 10 days, does accumulate in patients older th an 70 years of age. Methods. - Accumulation criteria were an increase of plasma anti-Xa and ant i-IIa levels determined prior to the first injection and on days 2, 5 7 and 10. The characteristics of the 30 consecutive included patients receiving tinzaparin at treatment dose (six men, 24 women) were: age 87 0 +/- 5.9 yea rs (range: 71-96 years), body weight: 62. 7 +/- 14. 6 kg (range: 38-90 kg) and creatinine clearance 40. 6;+/- 15.3 mL/ min (range: 20-72 mL/min). Results. - None of the patients required a dose adjustment of tinzaparin ov er the 10-day treatment period. Anti-Xa and anti-IIa activity levels on day 2 were 0.66 +/- 0.20 IU/mL (range: 0.26-1.04 IU/mL) and 0.33 +/- 0. 10 IU/ mL (range: 0. 18-0.55 IU/mL), respectively. These levels did not significan tly change over the 10 days. These results favor the absence of the accumul ation effect of tinzaparin. There was no correlation between anti-Xa and an ti-IIa activities and age, weight, or creatinine clearance. Concerning the side-effects, only one minor hematoma at the injection site was reported. Conclusion. - Tinzaparin may thus be administered in older patients with re nal impairment, at a treatment dose (1 75 anti-Xa IU/kg/d) for a 10-day tre atment period, without accumulation effect nor hemorrhagic side-effect in p atients with creatinine clearance greater than 20 mL/min. (C) 2001 Editions scientifiques et medicales Elsevier SAS.