Heme & HIV

Heparin

Medication

• Binds with antithrombin III

• Inactivates factors IXa, Xa, XIIa, XIII

• PK:

  • protein bound

  • Metabolized by liver, renal excretion (avoid in advanced hepatic dx)

  • Avoid in pork allergy

  • Caution in pregnancy - but it is the AC of choice d/t its inability to cross the placenta and it is NOT in the breastmilk,

LMWH

Smaller molecular size than heparin

• Inactivates factor Xa (enoxaparin)

• Selectively inhibits antithrombin III and factor Xa (fondaparinux)

• Avoid in pork allergy

• Caution in renal & hepatic dx, untreated HTN, retinopathy

• Caution in pregnancy - but it is the AC of choice d/t its inability to cross the placenta and it is NOT in the breastmilk,

Heparin(s) ADRs

__ ADRs

• HIT

• Anemia

• Life-threatening bleeding

• Injection site reactions

Protamine (sulfate)

Antidote for heparin (off-label for LMWH)

Onset = 5 min

Half-life = 7 min

heparin interactions

__ interactions

• Cephalosporins

• PCN

• Warfarin

• Antiplatelets

• Thrombolytics

heparin monitoring

__ monitoring

• ACT - poor correlation

• aPTT - can be influenced by vit K deficiency, liver dx, hemodilution but used for monitoring efficacy/concentration

• Anti-Xa - more rapidly reaches therapeutic levels, requiring fewer dosage adjustments

warfarin

Vitamin K inhibitor

• Inhibits formation of new vit K dependent factors (II, VII, IX, and X)

• Depletes proteins C and S

• PK

  • Highly protein bound

  • CYP 1A2 and 2C9

  • Excreted in urine

  • Half-life 3-4d

  • Therapeutic effects not seen until factors naturally clears = 3-4d

Warfarin interactions

__ interactions

• 2nd & 3rd gen cephalosporins

• High doses of PCN

• Increase __ efficacy

  • Bactrim, fluoroquinolones, metronidazole, macrolides, antifungals

• Decrease