Time-course of anti-Xa effects of calcium heparin and low-molecular-weight heparin given s.c.: insights for thrombosis prevention.
Thirty healthy volunteers underwent a pharmacokinetic study to control the effect of calcium heparin and low-molecular-weight heparin on coagulation factors. Activated partial thromboplastin time (aPTT), thrombin time (TT) and inhibition of activated factor X (Xa) were checked after a single subcutaneous administration of calcium heparin, 5000 IU (CH group); low-molecular-weight heparin 7500 AXaU (LMWH-LD group); and LMW heparin, 15,000 AXaU (LMWH-MD group). The mean values of aPTT rose significantly only after administration of LMW heparin (15,000 AXaU), while no relevant variations were observed after CH and LMWH-LD administration. The effects on TT were also very small and not relevant to an anticoagulant response. The Xa inhibitory effect exerted by the two LMW heparin doses proved substantially higher and longer-lasting than the effect of unfractioned heparin. A statistically significant Xa inhibition was still present 24 h after LMWH-MD administration and 16-20 h after LMWH-LD administration, while 6 h after CH administration no effect was detectable. The laboratory results confirm the marked antithrombophylic action, without relevant anticoagulant effects, already attributed by other authors to the new LMW heparin under study.
Romeo
G
G
Institute of Surgical Semeiotics, University of Catania, Italy.
Salanitri
G
G
Catania
G
G
D000328:Adult; D015951:Factor Xa; D005260:Female; D006493:Heparin / Q000494:pharmacology*; D006495:Heparin, Low-Molecular-Weight / Q000494:pharmacology*; D006801:Humans; D008297:Male; D010314:Partial Thromboplastin Time; D015842:Serine Proteinase Inhibitors; D013918:Thrombin Time; D013927:Thrombosis / Q000517:prevention & control*
D006495:Heparin, Low-Molecular-Weight; D015842:Serine Proteinase Inhibitors; C006871:calcium heparin; D006493:Heparin; D015951:Factor Xa