title: Elderly patients treated with tinzaparin (Innohep) administered once daily (175 anti-Xa IU/kg): anti-Xa and anti-IIa activities over 10 days.
abstract: Since low molecular weight heparins (LMWH) are partly eliminated by renal excretion, their pharmacodynamic profile may be modified in very elderly patients with age-related renal impairment. The aim of this prospective study was to determine whether tinzaparin (Innohep) 175 anti-Xa IU/kg administered subcutaneously once daily over 10 days does accumulate in hospital patients greater than 70 years of age. Plasma anti-Xa and anti-IIa amidolytic levels and APTT were determined prior to the first injection (day 0), and then, at peak level i.e. 5 h after the second injection (day 2) and subsequently on days 5, 7 and 10. Thirty consecutive inpatients (6 men, 24 women) requiring LMWHs at a curative dose for acute thromboembolic disease were included. Patients' characteristics (mean +/- SD) were: age 87.0+/-5.9 years (range 71-96), body weight 62.7+/-14.6 kg (range 38-90) and creatinine clearance 40.6+/-15.3 mL/min (range 20-72). The mean actual dose of tinzaparin delivered was 174.8 anti-Xa IU/kg. Since no patient had an anti-Xa activity above 1.5 IU/mL, the dose of tinzaparin remained fixed over 10 days. Anti-Xa and anti-IIa peak levels measured on day 2 were 0.66+/-0.20 IU/mL (range 0.26-1.04) and 0.33+/-0.10 IU/mL (range 0.18-0.55), respectively. Ex vivo anti-Xa/anti-IIa ratios were close to 2.1. APTT ratios (patient/control) were strongly correlated with anti-IIa activity (p <0.01). There was no progressive increase of the anti-Xa and anti-IIa activities after repeated administration of tinzaparin over the 10 day treatment period. No correlation was found between anti-Xa and anti-IIa activities and age, weight, or creatinine clearance. No major bleeding occurred during the study and only one minor haematoma at the injection site was reported. No thrombo-embolic complication or death occurred. Tinzaparin may thus be administered safely at a treatment dose (175 anti-Xa IU/kg) in older patients with age-related renal impairment. Neither dose adjustment, nor serial anti-Xa activity monitoring seems to be required in patients with creatinine clearance above 20 mL/min during the first ten day treatment.
authors: Laboratoire d'Hématologie, H pital Charles Foix, Ivry/Seine, France. virginie.siguret@cfx.ap-hop-paris.fr
authors: V
authors: V
authors: Siguret
authors: E
authors: E
authors: Pautas
authors: M
authors: M
authors: Février
authors: C
authors: C
authors: Wipff
authors: B
authors: B
authors: Durand-Gasselin
authors: M
authors: M
authors: Laurent
authors: J P
authors: JP
authors: Andreux
authors: M
authors: M
authors: d'Urso
authors: P
authors: P
authors: Gaussem
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015951:Factor Xa / Q000378:metabolism; D005260:Female; D005343:Fibrinolytic Agents / Q000008:administration & dosage* / Q000009:adverse effects; D006470:Hemorrhage / Q000139:chemically induced; D006495:Heparin, Low-Molecular-Weight / Q000008:administration & dosage* / Q000009:adverse effects; D006801:Humans; D007279:Injections, Subcutaneous; D008297:Male; D011446:Prospective Studies; D011516:Prothrombin / Q000378:metabolism; D013927:Thrombosis / Q000097:blood / Q000188:drug therapy*; D000078222:Tinzaparin
chemical_list: D005343:Fibrinolytic Agents; D006495:Heparin, Low-Molecular-Weight; D000078222:Tinzaparin; D011516:Prothrombin; C025337:Factor IIa; D015951:Factor Xa