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Warfarin, Your Days are Numbered!. Linda R. Kelly PharmD PhC CACP Pharmacy Anticoagulation Specialist Presbyterian Healthcare System. Objectives. Identify and classify the available oral anticoagulants Evaluate patient characteristics that would suggest using one product over another
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Warfarin, Your Days are Numbered! Linda R. Kelly PharmD PhC CACP Pharmacy Anticoagulation Specialist Presbyterian Healthcare System
Objectives • Identify and classify the available oral anticoagulants • Evaluate patient characteristics that would suggest using one product over another • Design a plan for switching from one oral anticoagulant to another • Manage oral anticoagulants in the peri-procedural period
Terminology • VKA-Vitamin K Antagonist (warfarin) • DOAC-Direct Oral Anticoagulant • TSOAC-Target Specific Oral Anticoagulant • NOAC-Novel (or New or Non-vitamin K) Oral Anticoagulant
Available Direct Acting Oral Anticoagulants (DOACs) • Dabigatran • Rivaroxaban • Apixaban • Edoxaban
DOAC Indications and Dosing Focus on Venous Thromboembolism and Non-valvular Atrial Fibrillation
Meet Marge Marge is a 72 year old female with non-valvular atrial fibrillation (NVAF). She has been taking warfarin for stroke prevention. Her history also includes hypertension. What is her CHA2DS2-VASc score?
Marge Marge comes to see you about starting a new product, bringing you a souvenir from her latest excursion. What factors should be considered when planning to start or switch a patient to a DOAC?
DOAC Indications and Dosing NVAF DVT PE
DOAC Indications and Dosing NVAF DVT PE
DOAC Renal Dosing **No dose reduction in DVT/PE patients. However, patients with SCr > 2.5 or CrCl < 25 mL/min not studied
DOAC Hepatic Dosing Child- Pugh Score calculator can be found at PresNet Anticoagulation Oral Anticoagulants Rivaroxaban (Xarelto) Child-Pugh Classification Score
DOAC Hepatic Dosing Child- Pugh Score calculator can be found at PresNet Anticoagulation Oral Anticoagulants Rivaroxaban (Xarelto) Child-Pugh Classification Score
Drug Interactions • Dabigatran: • Substrate for p-glycoprotein • Rivaroxaban: • Substrate for p-glycoprotein • 51% CYP 3A4 metabolism • Apixaban: • Substrate for p-glycoprotein • 25% CYP 3A4 metabolism • Edoxaban • Substrate for p-glycoprotein • Minimal CYP 3A4 metabolism
Drug Interactions Common Interacting Classes • Anticonvulsants including barbiturates • Antiretrovirals • Antifungals • Antiplatelet drugs and NSAIDS Your favorite drug interaction program is your best friend
Oral Anticoagulant Product Selection Focus on Venous Thromboembolism and Non-valvular Atrial Fibrillation
Is a DOAC a Good Choice For Marge? What should we consider before prescribing a DOAC?
DOAC Selection • DVT of leg or PE withactivecancer • Pregnant • DVT of leg or PE without active cancer
Anticoagulant Selection • Valvular atrial fibrillation • Valve replacement • Myocardial infarction requiring dual antiplatelet therapy • Breast feeding
Anticoagulant Selection • Valvular atrial fibrillation • Valve replacement • Myocardial infarction requiring dual antiplatelet therapy • Pregnant or breast feeding Does patient have CrCl < 30, mechanical heart valve, moderate to severe hepatic impairment (Child-Pugh B or C), significant drug-drug interactions6? Yes No • Non-valvular atrial fibrillation • Secondary VTE prevention • VTE prophylaxis following knee/hip replacement surgery Will the patient have trouble paying for a DOAC? Yes No
Anticoagulant Selection Does patient have CrCl < 30, mechanical heart valve, moderate to severe hepatic impairment (Child-Pugh B or C), significant drug-drug interactions6? Patient/ Family Preference Yes No • Patient Characteristics Favoring DOAC • Highly like to be adherent with DOAC therapy and follow up plan • Reliable to notify health care provider about changes to health and pertinent medical issues • Confirmed ability to obtain DOAC on a longitudinal basis from a financial, insurance coverage and retail availability standpoint • Unstable diet or malnutrition • Frequent illness or health status changes • Frequent medicine changes or need for medications that interact with warfarin but not with DOAC • Frequent medical procedures with bleeding risk
Anticoagulant Selection Patient/ Family Preference • Drug 1 • Older, more established • Strong interaction with diet and other medications • Reversible and easily monitored • Frequent monitoring and dose changes often required • Bridging may be required around procedures • Higher risk of intracranial hemorrhage • Drug 2 • Newer, less familiar • No diet interaction and fewer interactions with other medications • Cannot easily monitor level of anticoagulation and reversal agent may not be readily available • Frequent monitoring and dose changes not required • Bridging NOT required around procedures • Lower risk of intracranial hemorrhage
Drug affordability • Warfarin $ • Rivaroxaban, Apixaban, Dabigatran, Edoxaban $$$$ • Commercial plans (not Medicare/ Medicaid) • Patient copay • Medicare • Consider coverage gap • TrOOP vs. Drug spend • Use sample card and/or coupon Sample clinic Patient pay
Drug affordability- Medicare • Medicare coverage gap or “Donut Hole” • Must pay deductible (PHS plan deductible= $0) • Copay ~$45 per month • Gap starts at $3700 total cost or “drug spend” • This is copay + balance insurance pays • In 2017, when in the gap patient pays ~51% cost for generic, ~40% for brand. • Out of gap at $4,950 paid in out of pocket expenses • True out of pocket cost= “TrOOP” • Cost the patient sees, copay, coinsurance, spending during the coverage gap
Drug Affordability- Medicare • Example- Rivaroxaban alone • Rivaroxaban total cost= $431.4 • Rivaroxaban copay = $45 • Will meet gap in 8.6 months ($3700) • After gap, drugs cost = $172.56 per month • TrOOP ($4950 to get out of gap) • $360 (on copays) before gap with no deductible • $690.24 (4 months in gap) • Drug spend for catastrophic = $4950 • After gap $21.57 (5%) (if patient is on other medications)
Drug Affordability- Medicare • Example – Warfarin alone • Warfarin total cost $6 (5 mg per day x 30 days. ) • Warfarin copay= $4 • Will not meet gap with warfarin • In the gap, warfarin cost approx $3 • After gap will pay $1.60 per month
Patient Assistance • Utilize patient savings cards • Sample Cards • 1st month free! Regardless of insurance plan. • Copy Card • $0 copay for commercial insurance • Samples may be available
Patient selections takeaway • LMWH preferred in patients with active cancer • DOAC preferred in patients with DVT/ PE • NVAF -2016 European and Canadian guidelines recommend DOAC over warfarin, 2014 AHA/ACC/HRS guidelines do not recommend one over the other • Must consider patient co-morbidities and ability to afford therapy
Enoxaparin TO/FROM DOAC Stop old medication and start new medication when the next dose is due Abo-Salem J Thromb Thrombolysis (2014)
DOAC TO DOAC Stop DOAC 1 and start DOAC 2 when the next dose is due Abo-Salem J Thromb Thrombolysis (2014)
DOAC to Warfarin/Warfarin to DOAC Abo-Salem J Thromb Thrombolysis (2014)
Warfarin to DOAC • Discontinue warfarin • Begin rivaroxaban when INR below 3.0 • Begin dabigatran or apixaban when INR below 2.0
DOAC to warfarin • Need overlap therapy until INR equal or above 2.0 • DOAC • May interfere with INR reading • Must use DOAC troughfor INR draw • Make clear to the patient that they MUST go in for an INR draw right before next DOAC dose is due. OR • LMWH • Transition like normal LMWH bridge per PMG policy. • Start LMWH when next DOAC dose due.
Anticoagulant Transitions • Warfarin to DOAC, DOAC to Warfarin ** INR < 3.0 for Rivaroxaban
Peri-procedural bridging • Avoid overlapping LMWH and DOACS • Can the procedure be delayed until patient is not on anticoagulation therapy? • Is the bleeding risk of procedure high enough to warrant DOAC interruption? • Consult bleed risk tables. • Can we delay procedure to increase time for elimination? • DOAC elimination based on renal function. • Resume DOAC after hemostasis is achieved • Low bleed risk: 24 hours • High bleed risk: 48-72 hours.
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