1. UCSDHS Anticoagulation Reversal Guidelines
The references which will help me to be the best pharmacist I can be as well as pass this warfarin dosing competency are:
UCSDHS Anticoagulation Reversal Guidelines
UCSDHS Warfarin Dosing Guidelines
‘Hitchhiker’s Guide to the Galaxy’ by Douglas Adams
Anticoag.ucsd.edu
Both a, b and d
e. These are the references one can and is encouraged to use while taking this test to supplement your clinical judgment

2. 5 mg alternating with 2.5 mg every other day 7.5 mg
83 yo Caucasian female (65 kg) with Hx of diabetes and hyperlipidemia is presenting with new onset afib. Physician wants to start anticoagulation w/ warfarin, ‘pharmacy to dose’. According to UCSD warfarin management guideline, what would be the recommended starting dose in this patient assuming there are no known DDI or other dose modifying factors present?
5 mg
2.5 mg
5 mg alternating with 2.5 mg every other day
7.5 mg
b. In accordance with UCSDHS warfarin management guidelines, recommended initial warfarin dose for Caucasian female > 70 yo is 2.5 mg

3. Call patient’s pharmacy if patient is not reliable/available
MD wants pharmacy to dose warfarin for a patient. Medication reconciliation states that patient is on WARFARIN PO, but no specifics. Baseline INR is 2.6. Prior to ordering warfarin for this patient you could/should:
Ask the patient
Call patient’s pharmacy if patient is not reliable/available
Check prior EPIC encounters if available
Start warfarin maintenance based on UCSD warfarin dosing guidelines
a, b and c are all possible options
e. UCSDHS warfarin therapy management guidelines will assist with therapy initiation. Since this patient is on warfarin as an outpatient, making an effort to establish patients actual dose is very important; answers a, b and c are all acceptable ways to do so.

4. Heparin drip or enoxaparin 1 mg/kg sq q12h plus warfarin 1 mg daily
43 yo male on warfarin 7.5 mg as an outpatient (stable home dose) for recent history of DVT gets admitted for knee replacement surgery. Pt held warfarin prior to admission as instructed and his INR on admission was Today is POD2, no s/sx of post-op bleeding and ortho team wants to restart his anticoagulation. What are your recommendations?
Heparin drip or enoxaparin 1 mg/kg sq q12h plus warfarin 1 mg daily
Heparin drip or enoxaparin 1 mg/kg sq q12h plus warfarin 5 mg daily
Heparin drip or enoxaparin 1 mg/kg sq q12h plus warfarin 7.5mg daily
Warfarin 7.5 mg daily
c. Re-starting the 7.5 mg (home dose) would be correct as patient is known to be stable on it. Heparin or enoxaparin are required for “bridge” therapy since DVT is recent.

5. Patient is still in dose-finding stage, needs quick outpatient f/u
This is a 29 yo Male with acute DVT who is being discharged today on 2.5 mg of warfarin daily. What would be your concern?
Patient is still in dose-finding stage, needs quick outpatient f/u
INR is therapeutic, I am done here
2.5 mg may not be enough, too soon to tell.
Both a and c
d. This patient is clearly not at steady-state, so both answers a and c are correct

6. 35 yo AA male (98kg) presented with SOB and found to have a PE
35 yo AA male (98kg) presented with SOB and found to have a PE. Pt has no past medical history. Heparin gtt was started and physician wants to start warfarin as well. Using UCSDHS warfarin dosing guideline, the starting dose should be:
2.5 mg
5 mg
7.5 mg
10 mg
d. In accordance with UCSDHS warfarin management guidelines, recommended initial warfarin dose for African American male < 70 yo is 7.5 mg, however the guidelines also recommend to consider increasing the starting dose by 2.5 mg or 50% (whichever is less) for pts w/ Wt>90kg

7. Re-starting home dose is appropriate
72 yo female was admitted with SIRS/sepsis. She has a recent history of PE. Her INR on admission was 4.9, her home warfarin dose was 3mg M-F and 6 mg on S/S. Warfarin was held for 2 days and patients INR is 2.2 today when you are asked to re-start therapy. Patient is still on broad spectrum antibiotics and requires off-and-on blood pressure support. What would be the most appropriate regimen for this patient today?
Re-starting home dose is appropriate
30-50% reduction in home dose is appropriate as patient is still acutely ill
Continue to hold warfarin
30-50% increase in home dose is appropriate to account for missed doses
b. While it is important to maintain therapeutic anticoagulation in light of recent PE, acute severe illness necessitates 30-50% decrease in dose as warfarin/Vit K-dependent clotting factor metabolism may be altered.

8. 43 yo F on warfarin for hx of DVT who was stable on 6 mg po daily with INRs between 2 and 3 for the last several days. This morning you find out that she has been started on carbamazepine for seizure she suffered last night. You anticipate that this patient’s warfarin requirement will:
Increase
Decrease
Stay the same
a. Carbamazepine is a known CYP P450 inducer and may increase warfarin metabolism resulting in decreased therapeutic effect

9. Since INR goal is 2.5-3.5, would reduce dose by ~ 50%
70 yo M on warfarin for hx of MVR (mechanical) was re-started on warfarin. He was started on 7.5 mg (his home dose) and his INRs were as follows: Your next step would be:
Day 1
Day 2
Day 3
1.1
1.3
2.2
Hold dose
Since INR goal is , would reduce dose by ~ 50%
Continue same dose
Panic and call AC specialist
b. UCSDHS warfarin management guidelines recommend adjusting warfarin dose when a steep increase in INR is noticed on day 3 of therapy. Since therapeutic INR goal in this case is , there is a wider therapeutic threshold allowing clinician not to ‘hold’ dose, but rather decrease dose by 50%

10. Call HemeOnc for consult
70 yo M on warfarin for hx of MVR (mechanical) was re-started on warfarin. He was started on 7.5 mg (his home dose) and his INRs were as follows: Dose was reduced to 4 mg on Day 3 Day 4 INR is 3.6, what would you do now?
Day 1
Day 2
Day 3
INR
1.1
1.3
2.2
Dose
7.5 mg
4 mg
Hold dose
Reduce dose by 50%
Continue same dose
Call HemeOnc for consult
a. Even with therapeutic INR goal of 2.5 – 3.5, our patient is now supra-therapeutic. Since INR increase continues to be steep (>0.7) holding warfarin in now appropriate.

11. Nutrition w/ increased Vit K content Drug-drug interaction
70 yo M on warfarin for hx of MVR (mechanical) was re-started on warfarin. He was started on 7.5 mg (his home dose) and his INRs were as follows: What could be some of the reasons for this INR rise considering the staring dose was patients home dose (and he was stable on this dose prior to admission)?
Day 1
Day 2
Day 3
Day 4
1.1
1.3
2.2
3.6
Nutrition w/ increased Vit K content
Drug-drug interaction
Acute onset liver dysfunction
Relative Vit K deficiency resulting from NPO
Both b, c and d
e. Addition of new interacting medications, acute onset liver dysfunction, changes in nutritional status are ALL factors that can potentially affect warfarin metabolism or body’s response to warfarin and must be evaluated

12. Decrease warfarin dose to 1 mg for the next 5 days
62 yo F on warfarin for afib was admitted for a MRSA wound infection. She has been stable on 2 mg (home dose) of warfarin daily and is being discharged today with INR 2.3. Since you are dosing warfarin, team has asked you for discharge recommendations. You notice that she is being discharged with prescription for Bactrim DS 1 tab BID for 5 days. What would you recommend?
Decrease warfarin dose to 1 mg for the next 5 days
F/u promptly with Coumadin clinic
Continue with 2 mg
Both a and b
d. Sulfamethoxazole/Trimethoprim (as listed in both UCSD online resources) is expected to cause acute increase in INR, necessitating the empiric warfarin dose decrease; when medications strongly interacting with warfarin are initiated, prompt follow up should always be encouraged

13. Make sure the referral to clinic was ordered on discharge
Assuming the patient in previous question has history of follow-up with UCSD anticoagulation clinic, what could you do to ensure patient will follow up?
Make sure the referral to clinic was ordered on discharge
Call anticoagulation clinic and warn them
Send EPIC message to Anticoagulation clinic
Counsel the patient
Any of the above
e. All of the mentioned actions can be performed to ensure effective outpatient follow-up

14. A patient was admitted for afib ablation and is now being discharged on amiodarone 400 mg BID for 10 days followed by 200 mg daily along with their prior home warfarin. You know that amiodarone has profound effect on warfarin requirement. When will you anticipate the interaction to take full effect?
Immediately
In 1-2 days
In 6 months
Over 6-8 weeks
d. Although initial effect of amiodarone-warfarin drug interaction can be seen within days of co-administration, the full effect of amiodarone therapy on anticoagulation with warfarin takes place over 6-8 weeks.

15. Hold warfarin and give 5 mg IV Vitamin K
63 yo male on warfarin for atrial fibrillation (CHA2DS2-VASc score of 4) is admitted to medicine with CAP vs HCAP. He is started on vancomycin/zosyn/azithro. His INR on admission is 4.8. His hematology lab-work is normal and there is no apparent signs of active bleeding. You would: (use UCSD Anticoagulation Reversal Guideline to answer this)
Hold warfarin
Hold warfarin and give 5 mg IV Vitamin K
Hold warfarin and recommend MD to order FFP plus 5 mg IV Vit K
Hold warfarin and give 2.5 mg PO Vitamin K
Hold warfarin, recommend giving Kcentra 50 units/kg
a. UCSDHS anticoagulation reversal guideline suggests therapy interruption alone for INR<5 in the absence of bleeding

16. Patients on warfarin who are started on amiodarone should have their INR checked every 1-2 weeks over the next few months.
True
False
a. Full effect of amiodarone therapy on anticoagulation with warfarin takes place over 6-8 weeks

17. wine consumption < 1 - 2 glasses per day acute pneumonia infection
Please select ALL of the following factors which could change a patient's warfarin dose requirements: (use anticoag.ucsd.edu for reference)
daily multivitamin
mango consumption
wine consumption < glasses per day
acute pneumonia infection
acute CHF exacerbation
acute seasonal allergy symptoms
acute loss of appetite
green tea consumption
cranberry juice
grapefruit juice
a, b, d, e, g and h. All of these factors are have shown evidence of significant effect on anticoagulation with warfarin and are listed on anticoag.ucsd.edu website

18. 57 yo Hispanic male with severe liver disease and baseline INR of 1
57 yo Hispanic male with severe liver disease and baseline INR of 1.7 is starting on warfarin for portal vein thrombosis. The initial dose should be:
2.5 mg or less
5 mg
7.5 mg
10 mg
a. UCSDHS warfarin management guidelines recommend reducing the initial dose by 2.5 mg or 50% (whichever is less) in patients with liver disease

19. Check for recent changes/advancements in nutrition
64 yo female on warfarin for the past 4 months for PE, who is now inpatient with labs as follows: Where should you look for a possible cause of this?
Day 1
Day 2
Day 3
Day 4
Day 5
INR
2.1
2.4
2.6
1.9
1.5
Dose 4
Check for recent changes/advancements in nutrition
Check for medications started/administered on days 3 or 4
Check if patient’s overall condition is improving
All of the above
d. Addition of new interacting medications, change in patients medical condition (improvement vs deterioration), changes in nutritional status are ALL factors that can potentially affect warfarin metabolism or body’s response to warfarin and must be evaluated.

20. You started a patient on 5mg of warfarin, but INR remains at baseline the next day. Should the dose be increased?
Yes No
b. No dose change is warranted on the second day of warfarin therapy (unless INR rose > 0.5 the morning after dose #1) according to UCSDHS warfarin management guidelines

21. Increase warfarin to 7.5 mg Continue 5 mg for another day
55 yo M started on warfarin 5 mg according to UCSD inpatient management guideline. Labs are listed below: Considering, that there are no potential DDIs and patient is medically stable, your next step is:
Day 1
Day 2
Day 3
Day 4
INR
1.0
1.1
1.2
Dose 5
Increase warfarin to 7.5 mg
Continue 5 mg for another day
Decrease dose to 2.5 mg
None of the above
a. Guidelines recommend increasing dose on day 3-4 of therapy in the absence of INR response

22. Do nothing, this is all going according to plan
Patient developed a DVT, while hospitalized for major burn. Team started patient on enoxaparin bridge and asked you for help with warfarin. Lab values are as follows: Today you notice MD discontinued enoxaparin. You should:
Day 1
Day 2
Today
INR
1.1
1.3
2.2
Dose
5 mg
Call MD, ask to re-start enoxaparin; decrease today’s warfarin dose to 2.5 mg or hold warfarin
Do nothing, this is all going according to plan
Decrease today’s warfarin dose or hold warfarin. Enoxaparin should be discontinued
Stop both medications, ask MD to order 2.5 mg of Vitamin K
a. INR increase is a reflection of excessive warfarin dose (Facto VII inhibition) and does not confer therapeutic anticoagulation. “Bridge” therapy should be continued and warfarin dose should be decreased 50%.

23. 69 yo male with history of alcohol abuse, methamphetamine use (w/ resultant cardiomyopathy) and hypertension (SBP~140) has developed afib and is being started on warfarin. His CHA2DS2-VASc and HASBLED scores are: (use for reference)
4 and 4
3 and 3
4 and 2
2 and 1
b. CHA2DS2-VASc points for CHF, HTN and Age\ HASBLED points for Age, Drug abuse and Alcohol abuse. Note: HASBLED only scores HTN if >160 mmHG

24. no change in INR would be expected
Starting patient on continuous tube feedings is expected to have what effect on the INR of patient on a stable warfarin dose?
decrease INR
increase INR
no change in INR would be expected
a. Continuous tube feedings provide high and consistent Vit K supplementation as opposed to PO diet where Vit K content may vary daily.

25. no change in INR would be expected
Your patient on warfarin was stable on 5 mg dose, but started continuous tube feedings. INR became sub-therapeutic and you had reacted by increasing warfarin dose. Today your patient is back on oral diet. What might happen to patients’ INR?
INR might increase
INR might decrease
no change in INR would be expected
a. Stopping continuous tube feedings, will cause an intermittent decrease in Vit K intake, potentially leading to increase in INR

26. Patient is a 90 yo female, what would you have done differently?
Nothing, everything seems fine
Vit K administration is unnecessary, just holding the dose would be sufficient
Should not have started this patient on 5 mg, dose should have been reduced on 9/15
Patient has HIT, bivalirudin drip should be started
c. Age of the patient calls for initial dose adjustment to at least 2.5 mg (in the absence of any other factors) according to UCSDHS guidelines. Sharp INR rise (1.3->2.3) should have triggered dose reduction.

27. 71 yo Asian male (68kg) with HTN admitted for small bowel obstruction
71 yo Asian male (68kg) with HTN admitted for small bowel obstruction. Post-operatively, patient was started on Ampicillin/Cipro/Metronidazole and placed on TPN. On POD1, pt developed afib and was started on amiodarone and heparin drips. It is now POD5, pt was advanced to PO diet and the team wants pharmacist to assist with warfarin dosing. What would the initial dose recommendation be for this patient?
2.5 mg
5 mg
7.5 mg
1 mg
d. Starting dose for an Asian female >70yo is 2.5 mg. Dose should further be decreased since this patient is starting on metronidazole, amiodarone and parenteral nutrition.

28. Incorrect initial dose selection
What is the most likely cause of quick INR rise in this 58 Yo Hispanic Female?
Incorrect initial dose selection
Patient clearly had mango for lunch on 9/15
Patient probably has very low Vit K stores, judging by her weight
Patient must be taking a medication, that is a strong CYP2C9 inducer
Both a and c
e. UCSD guideline calls for 2.5 mg starting dose for this patient. Vit K stores can potentially be low in patients with extremely low weight.

29. What would you do differently in the case below?
I would administer some PO vit K
I would have continued apixaban
I would not have titrated the dose this quickly
nothing, no harm –no foul
c. Because of warfarin’s slow onset and long half-life, dose titration should not be done more frequently than every 48 to 72 hrs (unless patient experiences a sharp increase in INR)

30. None – avoid Enoxaparin
43 yo male patient with history of ESRD (on HD), DM, HTN, and PE 2 months ago (on warfarin) presents to ED for URI symptoms.  Patient has been stable on current warfarin dose of 3 mg po q day; however, he admits to missing a few doses of warfarin a week ago. He is being discharged home.  Which LMWH dose is appropriate for bridging this patient?
Today's labs:
Hgb  9.3  mg/dL
est CrCl  12 ml/min
INR  1.5 Weight 80 kg
Enoxaparin 40 mg SQ daily
Enoxaparin 80 mg SQ BID
Enoxaparin 30 mg SQ BID
Enoxaparin 120 mg SQ daily
None – avoid Enoxaparin
e. Enoxaparin is contraindicated in patients w/ ESRD

31. No, continue the current dose
43 yo male patient with history of ESRD (on HD), DM, HTN, and PE 2 months ago (on warfarin) presents to ED for URI symptoms.  Patient has been stable on current warfarin dose of 3 mg po q day; however, he admits to missing a few doses of warfarin a week ago due to having company and being distracted. MD wants to increase warfarin dose to get patient to therapeutic range, do you agree?
Today's labs:
Hgb  9.3  mg/dL
est CrCl  12 ml/min
INR  1.5 Weight 80 kg
Yes, increase the warfarin dose as the patient has not missed any warfarin doses in the last week
Yes, increase the warfarin dose as the patient did not miss yesterday's warfarin dose
No, continue the current dose
c. Low INR is likely the result of missed doses and will likely normalize on the current (stable) dose.

32. Hold warfarin and give 5 mg IV Vitamin K
57 yo female on warfarin for DVT. She is seen in ED for severe back pain and will be admitted for pain management. Her INR on admission is She not having desire to eat because of the pain for close to a week. She was adherent to her warfarin regimen. Her hematology lab-work is normal and there is no apparent signs of active bleeding. You would: (use UCSD Anticoagulation Reversal Guideline to answer this)
Hold warfarin
Hold warfarin and give 5 mg IV Vitamin K
Hold warfarin and recommend MD to order FFP plus 5 mg IV Vit K
Hold warfarin and give mg PO Vitamin K
Hold warfarin, recommend giving Kcentra 50 units/kg
d. UCSDHS anticoagulation reversal guideline suggests using oral Vit K for INR>10 in the absence of bleeding

33. Loading dose amiodarone (IV)
Please select ALL of the following medications which should warrant a stable warfarin dose to be changed empirically when this medication is initiated: (use anticoag.ucsd.edu for reference)
Loading dose amiodarone (IV)
Initiating amiodarone dose 200 mg BID (PO)
Azithromycin
Fluconazole
Sulfamethoxazole/ TMP
Augmentin
Metronidazole
Rifampin
a, d, e, g and h. All of these medications have shown evidence of significant effect on anticoagulation with warfarin and are listed on anticoag.ucsd.edu website

34. Warfarin 1 mg tabs with instruction to take 6 and ½ tabs PO qday
This patient is being discharged today. MD asks what he should write in a prescription, you say:
Warfarin 6.5 mg tab po q day
Warfarin 1 mg tabs with instruction to take 6 and ½ tabs PO qday
Warfarin 3 mg tabs with instruction to take 2 tabs (6mg) PO Monday thru Saturday and 3 tabs (9mg) on Sunday
c. Home regimen should be recommended based on the ease and convenience of administration as well as available tablet strengths