[Monitoring of tinzaparin in a ten day treatment dose in elderly patients].
OBJECTIVE
Renal impairment, which is frequently observed in elderly patients, raises the question of low molecular weight heparins treatment dose adjustment in this population. Thus, we conducted a prospective study to determine whether tinzaparin, administered subcutaneously at treatment dose (175 anti-Xa IU/kg) once daily for 10 days, does accumulate in patients older than 70 years of age.


METHODS
Accumulation criteria were an increase of plasma anti-Xa and anti-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 years (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 over 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 significantly change over the 10 days. These results favor the absence of the accumulation effect of tinzaparin. There was no correlation between anti-Xa and anti-IIa activities and age, weight, or creatinine clearance. Concerning the side-effects, only one minor hematoma at the injection site was reported.


CONCLUSIONS
Tinzaparin may thus be administered in older patients with renal impairment, at a treatment dose (175 anti-Xa IU/kg/d) for a 10-day treatment period, without accumulation effect nor hemorrhagic side-effect in patients with creatinine clearance greater than 20 mL/min.
Unité gériatrique aiguë, hôpital Charles-Foix, avenue de la République, 94205 Ivry-sur-Seine, France. eric.pautas@cfx.ap-hop-paris.fr
E
E
Pautas
V
V
Siguret
M
M
d'Urso
M
M
Laurent
P
P
Gaussem
M
M
Février
B
B
Durand-Gasselin
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002318:Cardiovascular Diseases / Q000150:complications* / Q000188:drug therapy*; D003404:Creatinine / Q000097:blood; D004334:Drug Administration Schedule; D016903:Drug Monitoring; D015951:Factor Xa / Q000378:metabolism; D005260:Female; D005343:Fibrinolytic Agents / Q000378:metabolism* / Q000627:therapeutic use*; D006495:Heparin, Low-Molecular-Weight / Q000378:metabolism* / Q000627:therapeutic use*; D006801:Humans; D007279:Injections, Subcutaneous; D007676:Kidney Failure, Chronic / Q000150:complications* / Q000378:metabolism*; D008297:Male; D008657:Metabolic Clearance Rate; D011446:Prospective Studies; D011516:Prothrombin / Q000378:metabolism; D000078222:Tinzaparin
D005343:Fibrinolytic Agents; D006495:Heparin, Low-Molecular-Weight; D000078222:Tinzaparin; D011516:Prothrombin; C025337:Factor IIa; D003404:Creatinine; D015951:Factor Xa