the dirt on anticoagulants

Warfarin

Indication:

• afib
• mechanical valves
• DVT/PE

Overdose:

• bleeding to death: administer fresh frozen plasma (FFP) stat and give vit K (takes some days to work)
• only elevated INR (no active bleeding): hold coumadin, and give vit K if INR dangerously high

What's good about it?

• can be given as oral tabs (patient not subjected to shots all the time)
• CHEAP!

What's bad?

• takes a couple of days to reach a therapeutic level
• hard to reverse
• hard to regulate

Really bad stuff to watch out for:

• Warfarin skin necrosis (happens because protein c and s are the first to go, leaving factors 10, 9, 7, and 2 unopposed = proclotting phenomenon)

Heparin

Indication:

• DVT/PE (occurred in hospital)
• acute MI
• non-hemorrhagic stroke
• DIC

Overdose:

• bleeding to death = administer protamine sulfate!
• increased PTT = stop heparin 

Good:

• rapid action
• easy to monitor
• easy to reverse
• pregnant woman can use it

Bad:

• IV/SC only
• have to administer often (8 hours and with minimal gaps between administration to prevent thrombus formation [system overreacts in absence of heparin])
• variable response to same dose

Worse than bad:

• heparin induced thrombocytopenia (HIT): platelets drop down about 50% in a few days (<50,000). absolutely NO HEPARIN PRODUCTS
• thrombosis (arterial or wacky venous thrombosis)
• treat HIT by withholding ALL heparin products, argatroban, lepirudin. not even enoxaparin can be administered coz can cause HIT 5% of time.

Enoxaparin

Uses:

• acute MI
• DVT/PE
• pregnant women with DVT

Overdose:

• Active bleeding give FFP and stop treatment with drug

Why good?

• pregnant women can use it
• longer t1/2
• no monitoring (dose according to weight and get results)

Why bad?

• EXPENSIVE!
• SC
• HIT
• needs dose adjustment if patient hasRF