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Anticoagulation, antiplatelets, ACS and AF

38 Gulf Prometric Pharmacist (DHA, DOH, MOH, SCFHS, QCHP) practice questions on Anticoagulation, antiplatelets, ACS and AF, part of Clinical Pharmacy and Therapeutics. The first 25 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

  1. Question 1 · Medium

    Which pharmacogenetic variant reduces the antiplatelet effect of clopidogrel?

    1. ASLCO1B1 521T>C variant
    2. BCYP2D6 ultrarapid metaboliser status
    3. CCYP2C19 loss-of-function alleles
    4. DVKORC1 -1639 G>A variant
    Show answer

    Answer: C · CYP2C19 loss-of-function alleles

    Clopidogrel is a prodrug activated mainly by CYP2C19. Carriers of loss-of-function alleles form less active metabolite and have a higher risk of stent thrombosis and recurrent events, so ticagrelor or prasugrel may be chosen.

    • A: SLCO1B1 variants increase simvastatin myopathy risk.
    • B: CYP2D6 variation matters for codeine and tamoxifen.
    • D: VKORC1 variants alter warfarin dose requirements.

    Remember this

    CYP2C19 loss-of-function alleles reduce clopidogrel activation.

  2. Question 2 · Hard

    On day 7 of unfractionated heparin, a patient's platelet count falls from 280 to 90 x 10^9/L with a new DVT. What is the best next step?

    1. AStop all heparin; start argatroban
    2. BSwitch to enoxaparin at prophylactic dose
    3. CStart warfarin alone and stop heparin now
    4. DGive platelet transfusion and continue heparin
    Show answer

    Answer: A · Stop all heparin; start argatroban

    A fall of more than 50% in platelets between days 5 and 10 with new thrombosis suggests heparin-induced thrombocytopenia. All heparin, including flushes and LMWH, is stopped and a non-heparin agent started. Warfarin alone can worsen thrombosis, and platelets fuel thrombosis.

    • B: LMWH cross-reacts with the HIT antibody.
    • C: Warfarin alone can precipitate venous gangrene in HIT.
    • D: Transfusion with ongoing heparin worsens the process.

    Remember this

    Suspected HIT: stop all heparin and start a non-heparin anticoagulant.

  3. Question 3 · Medium

    A patient with triple-positive antiphospholipid syndrome and previous venous thrombosis needs long-term anticoagulation. Which drug is preferred?

    1. AApixaban
    2. BWarfarin
    3. CAspirin alone
    4. DRivaroxaban
    Show answer

    Answer: B · Warfarin

    In triple-positive antiphospholipid syndrome, DOACs were associated with more arterial thrombotic events, so warfarin is preferred. Aspirin alone is inadequate for a prior venous event.

    • A: Apixaban is also not advised in high-risk APS.
    • C: Aspirin alone does not prevent recurrent VTE.
    • D: Rivaroxaban had more events in the TRAPS trial.

    Remember this

    Triple-positive antiphospholipid syndrome: use warfarin, not a DOAC.

  4. Question 4 · Medium

    A patient on warfarin has an INR of 5.2 with no bleeding. What is the most appropriate management?

    1. AGive fresh frozen plasma to reverse it
    2. BContinue the same dose and recheck in a month
    3. COmit one or two doses, then restart lower
    4. DGive 10 mg of IV vitamin K immediately
    Show answer

    Answer: C · Omit one or two doses, then restart lower

    For an INR between 4.5 and 10 without bleeding, routine vitamin K is not recommended. Warfarin is withheld for a dose or two and resumed at a lower dose once the INR falls to range.

    • A: Plasma is for major bleeding.
    • B: Continuing unchanged leaves a high bleeding risk.
    • D: High-dose IV vitamin K risks warfarin resistance and is unnecessary.

    Remember this

    INR 4.5-10 without bleeding: hold warfarin briefly, with no routine vitamin K.

  5. Question 5 · Easy

    In the CHA2DS2-VASc score, which factor is worth 2 points?

    1. APrevious stroke or TIA
    2. BFemale sex
    3. CHypertension
    4. DDiabetes mellitus
    Show answer

    Answer: A · Previous stroke or TIA

    Prior stroke, TIA or thromboembolism and age 75 or older each score 2 points. Heart failure, hypertension, diabetes, vascular disease, age 65-74 and female sex score 1 point each.

    • B: Female sex scores 1 point.
    • C: Hypertension scores 1 point.
    • D: Diabetes scores 1 point.

    Remember this

    CHA2DS2-VASc: prior stroke or TIA and age 75 or older score 2 points each.

  6. Question 6 · Medium

    A patient develops a first unprovoked proximal DVT and has no bleeding risk factors. What treatment duration is recommended initially?

    1. AAt least 3 months, then review
    2. BSix weeks of anticoagulation only
    3. CTwo weeks of anticoagulation in total
    4. DLifelong therapy without any review

    Answer and explanation in LearnFree account

  7. Question 7 · Medium

    A patient on clopidogrel needs a proton pump inhibitor for gastroprotection. Which PPI is the preferred choice?

    1. AOmeprazole
    2. BEsomeprazole
    3. CPantoprazole
    4. DLansoprazole

    Answer and explanation in LearnFree account

  8. Question 8 · Easy

    For most patients on warfarin for atrial fibrillation or venous thromboembolism, the target INR is:

    1. A2.0-3.0
    2. B1.0-1.5
    3. C4.0-5.0
    4. D3.5-4.5

    Answer and explanation in LearnFree account

  9. Question 9 · Medium

    A patient starting ticagrelor after an MI reports breathlessness without chest signs. What explanation is most likely?

    1. ATicagrelor-induced irreversible pulmonary fibrosis
    2. BAnaphylaxis to ticagrelor needing withdrawal
    3. CAcute heart failure caused by ticagrelor
    4. DTicagrelor-related dyspnoea, usually mild

    Answer and explanation in LearnFree account

  10. Question 10 · Medium

    In which patient is prasugrel contraindicated?

    1. AA patient aged 55
    2. BA patient with a previous stroke or TIA
    3. CA patient with a recent NSTEMI
    4. DA patient weighing 80 kg

    Answer and explanation in LearnFree account

  11. Question 11 · Hard

    A 79-year-old man weighing 64 kg with atrial fibrillation has serum creatinine 150 umol/L. Using Cockcroft-Gault, which rivaroxaban dose is appropriate?

    1. A10 mg twice daily
    2. B2.5 mg twice daily
    3. C20 mg once daily with food
    4. D15 mg once daily with food

    Answer and explanation in LearnFree account

  12. Question 12 · Medium

    A woman on warfarin finds she is 7 weeks pregnant. What is the appropriate plan?

    1. AContinue warfarin throughout the pregnancy unchanged
    2. BSwitch to therapeutic LMWH and avoid warfarin
    3. CSwitch to rivaroxaban for the rest of pregnancy
    4. DStop all anticoagulation until after delivery

    Answer and explanation in LearnFree account

  13. Question 13 · Hard

    An 84 kg inpatient with a proximal DVT has a creatinine clearance of 24 mL/min. Enoxaparin is supplied as 100 mg/mL. What treatment dose and frequency are appropriate?

    1. A84 mg (0.84 mL) twice daily
    2. B84 mg (0.84 mL) once daily
    3. C42 mg (0.42 mL) once daily
    4. D168 mg (1.68 mL) once daily

    Answer and explanation in LearnFree account

  14. Question 14 · Medium

    Why is a parenteral anticoagulant overlapped with warfarin for the first days of treatment of acute VTE?

    1. AProtein C falls first, causing transient hypercoagulability
    2. BHeparin improves the absorption of warfarin from the gut
    3. CWarfarin transiently raises factor VII in the first few days
    4. DWarfarin has no anticoagulant effect for several weeks

    Answer and explanation in LearnFree account

  15. Question 15 · Medium

    What is the standard enoxaparin dose for venous thromboembolism prophylaxis in a hospitalised adult with normal renal function?

    1. A40 mg subcutaneously once daily
    2. B80 mg once daily
    3. C10 mg once daily
    4. D1 mg/kg twice daily

    Answer and explanation in LearnFree account

  16. Question 16 · Medium

    A patient weighing 70 kg with a creatinine clearance of 25 mL/min needs treatment-dose enoxaparin for a DVT. What is the appropriate dosing?

    1. A70 mg subcutaneously once daily
    2. B40 mg subcutaneously once daily
    3. C70 mg subcutaneously twice daily
    4. D1.5 mg/kg twice daily

    Answer and explanation in LearnFree account

  17. Question 17 · Medium

    A patient with a mechanical mitral valve needs long-term anticoagulation. What is the recommended agent?

    1. ADabigatran
    2. BRivaroxaban
    3. CWarfarin
    4. DApixaban

    Answer and explanation in LearnFree account

  18. Question 18 · Medium

    What is the correct immediate aspirin dose in a patient with suspected ACS who has not taken aspirin?

    1. A75 mg swallowed whole
    2. B300 mg chewed
    3. C1 g intravenously
    4. D600 mg every 4 hours

    Answer and explanation in LearnFree account

  19. Question 19 · Easy

    Titration of a continuous unfractionated heparin infusion is guided by which laboratory result?

    1. ABleeding time
    2. BPlatelet aggregation
    3. CINR
    4. DaPTT

    Answer and explanation in LearnFree account

  20. Question 20 · Medium

    Fondaparinux acts by:

    1. ADirect inhibition of free and clot-bound thrombin
    2. BSelective factor Xa inhibition via antithrombin
    3. CBlocking the P2Y12 receptor on platelets
    4. DInhibiting vitamin K epoxide reductase

    Answer and explanation in LearnFree account

  21. Question 21 · Hard

    An 83-year-old woman weighing 58 kg with atrial fibrillation has serum creatinine 110 umol/L. Which apixaban dose is correct?

    1. A2.5 mg once daily
    2. B10 mg twice daily
    3. C2.5 mg twice daily
    4. D5 mg twice daily

    Answer and explanation in LearnFree account

  22. Question 22 · Hard

    A fall in a patient on long-term warfarin causes a large subdural haematoma with confusion, and the INR is 4.8. Which reversal strategy is correct?

    1. AProtamine sulfate infusion
    2. BOral vitamin K 2.5 mg and observation
    3. C4-factor PCC plus IV vitamin K
    4. DFresh frozen plasma on its own

    Answer and explanation in LearnFree account

  23. Question 23 · Medium

    A patient on a heparin infusion has an aPTT ratio of 3.5 (target 1.5-2.5). What is the best response?

    1. ASlow or pause the infusion, then recheck aPTT
    2. BStop heparin and give oral warfarin alone
    3. CGive vitamin K to reverse the heparin
    4. DIncrease the infusion rate to keep levels steady

    Answer and explanation in LearnFree account

  24. Question 24 · Hard

    A patient on a stable warfarin dose of 35 mg weekly has an INR of 1.6 (target 2-3) with no clear cause. Which revised weekly dose is appropriate?

    1. A40 mg per week
    2. B30 mg per week
    3. C45 mg per week
    4. D50 mg per week

    Answer and explanation in LearnFree account

  25. Question 25 · Medium

    A 58-year-old man had a drug-eluting stent placed after an NSTEMI. What antiplatelet plan is standard for the first year?

    1. AClopidogrel alone for 1 month
    2. BAspirin plus ticagrelor or prasugrel for 12 months
    3. CAspirin alone for 12 months
    4. DWarfarin plus aspirin for 12 months

    Answer and explanation in LearnFree account

13 more Anticoagulation, antiplatelets, ACS and AF questions

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