Low Molecular Weight Heparins (LMWH's) (Last Updated - 3/10/2005)

-act primarily as inhibitors of Factor Xa (via anti-thrombin) not inhibition of thrombin (IIa)
-have < 18 monosaccharide units --> cannot bind thrombin (IIa) & anti-thrombin simultaneously to catalyze thrombin's (IIa) inhibition
     -simultaneous binding requires >= 18 units
-given sub-Q QD or BID in fixed or weight-adjusted doses
-minimal in vitro effex on coag labs --> no routine lab monitoring of PT's or aPTT's
-easier than heparin due to:
     1) More predictable pharmacokinetics --> weight-adjusted dosing with no routine lab monitoring
     2) Decreased side effex vs. heparin (Ex.) HIT, bleeding & osteoporosis)

-Cautions:
     -ESRD --> may require lab monitoring (prolonged 1/2-life of drug in ESRD)

-Uses:
     1) Venous Thromboembolism
     2) Venous Thrombosis
     3) Pulmonary Embolus (PE)
     4) Unstable Angina

-Drugs:
     1) Enoxaparin (Lovenox)
     2) Dalteparin (Fragmin)
     3) Ardeparin (Normiflo)
     4) Tinzaparin (Innohep) --> not FDA-approved
     5) Nadroparin (Fraxiparine) --> not FDA-approved
     6) Reviparin (Clivarine) --> not FDA-approved

========================================================
References:

Goodman & Gilman's: The Pharmacologic Basis Of Therapeutics - 10th Edition - 2001. Chapter 55.