Anticoagulants

Question 1

Low molecular weight heparins

Answer 1

Enoxaparin (Lovenox), dalteparin (Fragmin), tinzaparin (innohep), Fondaparinux (Arixtra)

Question 2

Direct thrombin inhibitors

Answer 2

Argatroban, lepirudin (Refludan) and bivalirudin (Angiomax)

Question 3

Heparin MOA

Answer 3

Binds to the natural anticoagulant antithrombin and accelerates its enzymatic activity, complex inhibits thrombin as well as other factors

Question 4

What molecules can form the bridge between AT and thrombin

Answer 4

heparin molecules at least 18 saccharide units

Question 5

What will Heparin not do

Answer 5

It will not dissolve an existing blood clot

Question 6

What does Heparin do

Answer 6

Only prevents propagation and growth

Question 7

What is the T1/2 of heparin

Answer 7

it is dose dependent but it usually ranges from 30-90 mins mins

Question 8

Heparin clearance is reduced in who

Answer 8

patients with renal and hepatic dysfunction

Question 9

How do we monitor heparin?

Answer 9

aPTT, ACT, anti-factor Xa activity, or protamine titration assay, aPTT is the most widely used; ACT is most commonly used during coronary angioplasty and CABG surgery

Question 10

ADR’s of Heparin

Answer 10

Bleeding, local irritation at injection site, thrombocytopenia, long-term use of heparin, alopecia, priapism, hyperkalemia, elevated ALT/AST and osteoporosis

Question 11

The antidote is available and very effective

Answer 11

Protamine

Question 12

HIT

Answer 12

severe, immune-mediated, drug-induced complication, usually indiacted by 50% drop in platelets or a platelet count ,150,000; typically the drop occurs 5-10 days into treatment

Question 13

What do you do if a patient develops HIT

Answer 13

stop all forms of heparin, be sure to check for flushes, heparin in TPN, and heparin coated catheters, order heparin antibody lab, use a direct thrombin inhibitor or fondaparinux

Question 14

What do you do if the heparin antibody lab is positive?

Answer 14

the patient should never get heparin ever, ever again

Question 15

Heparin clinical uses

Answer 15

treatment of venous thromboembolism, atrial fibrillation, prevention of VTE, acute coronary syndromes, maintaining patent IV line, intraoperative coagulation

Question 16

Low Molecular weight heparin

Answer 16

smaller molecular weight fragment obtained by chemical or enzymatic depolarization techniques of unfractionated heparin, similar to heparin, it prevents formation of thrombi

Question 17

LMWH products commercially available in the US

Answer 17

Enoxaparin (Lovenox), Dalteparin (Fragmin), Tinzaparin (Innohep), last 2 not used

Question 18

Smaller molecular weight prevents what

Answer 18

binding AT and thrombin simultaneously

Question 19

For all three LMWH

Answer 19

routine monitoring is not necessary, T1/2 is 3-6 hours, dose independent renal elimination, subcutaneous bioavailability >90%

Question 20

Routine efficacy monitoring of LMWH is

Answer 20

not recommended

Question 21

What is the most accurated method to monitor efficacy?

Answer 21

Anti-factor Xa levels

Question 22

how often do you measure LMWH

Answer 22

peak level 4 hours post dose at steady state

Question 23

Patients to consider monitoring

Answer 23

weight> 150 kg or ,50 kg, CrCL ,30 ml/min pediatric patients, pregnant patients

Question 24

Enoxaparin (Lovenox)

Answer 24

always adjust dose in renal failure, 1 mg/kg subcut Q12hr, always use actual body weight, don’t cap doses in obese

Question 25

ADRs of Enoxaparin (Lovenox)

Answer 25

bleeding (monitor Hgb/HCT), HIT but not as common as heparin

Question 26

Consider use of heparin over LMWH for pt with

Answer 26

obesity, renal failure, surgical candidates, or high risks for bleeding

Question 27

Clinical uses of Enoxaparin (Lovenox)

Answer 27

treatment of VTE, prophylaxis of VTE, prevention of thrombus in Afib, STEMI, NSTEMI

Question 28

Dalteparin (Fragmin)

Answer 28

LMWH, Prophylaxis and treatment of ACS, DVT/PE but not FDA approved for this

Question 29

Tinzaparine (Innohep)

Answer 29

LMWH

Question 30

Fondaparinux (Arixtra)

Answer 30

Factor Xa inhibitor, T1/2= 17-21 hours, will accumulate in renal impairment, no method of monitoring, no reversal agent

Question 31

Clinical uses of Fondaparinux (Arixtra)

Answer 31

VTE prophylaxis, post op joint replacement or abdominal surgery, STEMI and NSTEMI, treatment of PE or DVT

Question 32

Fondaparinux (Arixtra) serves as a great option for people who

Answer 32

have developed HIT

Question 33

Argatroban

Answer 33

a direct thrombin inhibitor, treatment and prophylaxis of HIT, cardiovascular procedures in place of heparin with HIT or suspected HIT, monitor with aPTT and infusion rates adjusted accordingly, $$$, adjust in hepatic

Question 34

Lepirudin (Refludan)

Answer 34

direct thrombin inhibitors, treatment and prophylaxis of HITT, cardiovascular procedures (in place of heparin) with HIT or suspected HIT, use is rare, adjust renal

Question 35

Bivalirudin (Angiomax)

Answer 35

direct thrombin inhibitor, continuous infusion during PCI, IV only $$$$, adjust renal

Question 36

Direct thrombin inhibitors

Answer 36

all given as continuous infusion- short T1/2 (25-75 mins), monitor aPTT to adjust dose