Low-molecular-weight heparin in patients with renal insufficiency.

Background: Low-molecular-weight heparins (LMWH) have been shown to be safer, more effective and more convenient than unfractionated heparin (UFH) in many clinical situations. However, their use is limited in patients with renal insufficiency (RI) due to bioaccumulation.

Method: The literature is critically reviewed and known pharmacokinetic properties are summarised. An approach to using LMWH in patients with RI is proposed on the basis of currently available evidence.

Results And Discussion: Pharmacokinetic data of commonly used LMWH and of UFH are summarised in respect of RI. Most data are known on enoxaparin. A dose reduction is recommended in patients with severe RI. Limited data on dalteparin and tinzaparin suggest that there is less bioaccumulation. However, further studies are needed, in respect of long-term use and clinical end-points in particular.There are no data on certoparin and only very limited data on nadroparin. A detailed approach is suggested for the use of LMWH in patients with severe RI. Briefly: (1) before using LMWH, evaluate the patient's renal function, ist expected course, imminent interventions, and general bleeding risk; (2) prefer LMWH to UFH in view of better efficacy and lower bleeding risk in general; (3) however, prefer i.v. UFH to s.c. LMWH if a patient is unstable, is awaiting emergency interventions, or has a high bleeding risk, since UFH can be stopped more quickly due to i.v. administration, has a shorter half-life time, and can be effectively antagonised; (4) prefer a well documented LMWH; use established dosing schemes; (5) monitor LMWH with peak anti-Xa levels in patients with severe RI regularly, and adjust dose to be in target range; (6) do not use LMWH in patients with severe RI if there is no possibility of measuring anti-Xa levels.

Conclusions: LMWH may be considered for patients with severe RI. However, experience, judicious choice and careful monitoring of patients with severe RI treated with LMWH are necessary.