Direct oral anticoagulants

1A 34-year-old woman has new atrial fibrillation. Echocardiography shows moderate rheumatic mitral stenosis. She is otherwise well, with normal renal function. What is the appropriate anticoagulant?

• Dabigatran 150 mg twice daily
• Apixaban 5 mg twice daily
• Warfarin
• Rivaroxaban 20 mg once daily with food
• No anticoagulation — she is young and has no other risk factors

2A 64-year-old man with an oesophageal adenocarcinoma, not yet resected, has a proximal DVT. Which anticoagulant does the animation say is preferred?

• Dabigatran
• Edoxaban
• Rivaroxaban
• Aspirin
• Low molecular weight heparin

3A 71-year-old woman with permanent atrial fibrillation had a surgical bioprosthetic mitral valve replacement six weeks ago. What does the animation say about her anticoagulation?

• Dabigatran, because the RE-ALIGN trial supports it after valve surgery
• Warfarin now; a DOAC can be used once three months have passed since the valve replacement
• Start a DOAC now; a bioprosthetic valve behaves like a native valve from the day of surgery
• Lifelong warfarin; DOACs are contraindicated with any prosthetic valve
• No anticoagulation is needed, because a bioprosthetic valve is not an indication for it

4In the atrial fibrillation trials, which outcome did the DOACs reduce by around half compared with warfarin?

• Ischaemic stroke
• All-cause mortality
• Gastrointestinal bleeding
• Intracranial haemorrhage
• Any bleeding of any severity

5Why does a patient who stops taking a DOAC carry a risk that is easier to miss than with warfarin?

• There is no routine test such as the INR to show it, and protection is lost within about a day
• DOAC levels are checked routinely, but the results take a week to return
• Stopping a DOAC causes a rebound rise in clotting factors for several weeks
• DOACs have a longer half-life than warfarin, so the effect lingers unpredictably
• Stopping a DOAC triggers heparin-induced thrombocytopenia

1An 81-year-old man with atrial fibrillation weighs 72 kg. His creatinine is 90 µmol/L and his creatinine clearance is 58 mL/min. He has no bleeding history. What apixaban dose should he be prescribed?

• Avoid apixaban and use warfarin
• Apixaban 2.5 mg twice daily, because he is over 80
• Apixaban 10 mg twice daily for 7 days, then 5 mg twice daily
• Apixaban 5 mg twice daily
• Apixaban 2.5 mg twice daily, because his creatinine clearance is under 60

2A 76-year-old woman with atrial fibrillation weighs 52 kg. Her creatinine is 98 µmol/L and her creatinine clearance is 35 mL/min. She is frail and has fallen twice this year. What apixaban dose should she be prescribed?

• None — falls are a contraindication to anticoagulation
• 5 mg twice daily
• 2.5 mg twice daily, because she is frail and has fallen
• 2.5 mg twice daily, because she weighs under 60 kg
• 2.5 mg twice daily, because she is over 75

3A patient with an acute pulmonary embolism is to be treated with dabigatran. Which is correct?

• Dabigatran 110 mg twice daily for 7 days, then 150 mg twice daily
• Dabigatran 110 mg twice daily from day one
• Dabigatran 150 mg twice daily from day one
• Dabigatran given together with low molecular weight heparin for the first 5 days
• At least 5 days of low molecular weight heparin first, then dabigatran at the standard dose unless reduction criteria apply

4A 70-year-old man with a creatinine clearance of 35 mL/min starts rivaroxaban for an acute pulmonary embolism. What does the animation say is correct?

• 15 mg twice daily for 3 weeks as usual; afterwards, 15 mg once daily may be considered if his bleeding risk outweighs his recurrence risk
• 15 mg once daily from day one, because his clearance is below 50
• The loading phase is shortened to 7 days because of his renal function
• 20 mg once daily from day one, with no loading phase
• Rivaroxaban cannot be used below a clearance of 50

5Which statement about apixaban 2.5 mg twice daily is correct?

• It is never used in atrial fibrillation
• It is the standard AF dose for anyone over 75
• It is the extended-prevention dose after six months of VTE treatment, and in AF it is used only when the AF reduction criteria are met
• It is the loading dose for an acute pulmonary embolism
• It can be started after three months of VTE treatment in any patient

1A 78-year-old woman with atrial fibrillation weighs 40 kg. Her serum creatinine is 95 µmol/L and the laboratory reports an eGFR of 53 mL/min/1.73 m². Her Cockcroft-Gault creatinine clearance is 27 mL/min. Which statement is correct?

• A DOAC is contraindicated at this level of renal function; she needs warfarin
• Rivaroxaban 20 mg once daily is appropriate because her eGFR is above 50
• Dabigatran 110 mg twice daily is appropriate because her eGFR is above 50
• Apixaban 5 mg twice daily is correct, as only one reduction criterion is met
• Dabigatran is contraindicated; apixaban 2.5 mg twice daily is an appropriate choice

2A patient on a DOAC has a creatinine clearance of 40 mL/min and is clinically stable. Using the rule of thumb in the animation, how often should renal function be rechecked?

• Monthly for the first year, then stop
• Once a year, whatever the clearance
• About every 4 months, and after any acute illness
• Only if the patient develops symptoms
• Every 6 weeks

3A patient with atrial fibrillation is on haemodialysis. Which statement matches the UK Kidney Association guidance described in the animation?

• Apixaban 2.5 mg twice daily or a vitamin K antagonist are options; this is beyond the licence, and no anticoagulation is a legitimate choice
• Edoxaban 60 mg once daily, because it is the least renally cleared
• Dabigatran 110 mg twice daily, timed after dialysis sessions
• Rivaroxaban 15 mg once daily is the licensed choice on dialysis
• Anticoagulation is mandatory, and any DOAC may be used at full dose

4A 55 kg woman with normal renal function and no interacting drugs starts edoxaban for a pulmonary embolism, after 5 days of low molecular weight heparin. What dose?

• 30 mg twice daily
• 60 mg once daily, because weight only matters in atrial fibrillation
• 60 mg twice daily
• 30 mg once daily
• 15 mg once daily

5Three weeks after a sleeve gastrectomy, a patient develops a DVT. According to the animation, what is the most appropriate anticoagulant?

• Apixaban 5 mg twice daily, as it is less affected by gastric surgery
• Low molecular weight heparin
• Dabigatran, because it is absorbed in the colon
• Edoxaban 30 mg once daily
• Rivaroxaban 20 mg once daily with food

1A 46-year-old man has been taking apixaban 5 mg twice daily for an unprovoked pulmonary embolism diagnosed two months ago. He is now starting standard four-drug antituberculous therapy including rifampicin. What should happen to his anticoagulation?

• Switch to rivaroxaban 20 mg once daily, which is less affected
• Switch to low molecular weight heparin or warfarin for the duration of rifampicin treatment, and for about two weeks after it stops
• Continue apixaban 5 mg twice daily and monitor for symptoms
• Increase apixaban to 10 mg twice daily while on rifampicin
• Stop anticoagulation until the rifampicin course is complete

2A 72-year-old with atrial fibrillation on dabigatran 150 mg twice daily is started on verapamil. What change does the animation describe?

• Switch to dabigatran 220 mg once daily
• Stop dabigatran — verapamil is a contraindication
• Reduce dabigatran to 75 mg twice daily
• Reduce dabigatran to 110 mg twice daily
• No change is needed

3A patient on edoxaban 60 mg once daily for VTE needs a course of erythromycin. What should happen to the edoxaban?

• Reduce to 30 mg once daily while on erythromycin
• No change — the interaction rule applies only in AF
• Hold edoxaban for the course
• Increase to 60 mg twice daily
• Stop edoxaban and switch to dabigatran

4A carer wants to put a patient’s dabigatran into a weekly dosette box and open the capsules to mix with food. What advice is correct?

• The dosette box is fine, but do not open the capsules
• Both are fine
• Neither — keep it in the original packaging and never open the capsules
• Crush the capsule contents instead
• Opening the capsules is fine, but do not use a dosette box

5A patient on warfarin for recurrent VTE is switching to rivaroxaban. At what INR should rivaroxaban be started?

• 3.0 or less
• Below 2.0
• At any INR, stopping warfarin the same day
• Only once the INR is in the 2–3 range, overlapping for 2 days
• 2.5 or less

1Two patients each take their DOAC at 08:00 and 20:00. Both realise at 16:00 that they missed the morning dose. One takes dabigatran 150 mg twice daily, the other apixaban 5 mg twice daily. According to the product information, what should each do?

• Dabigatran: skip the missed dose. Apixaban: take it now, then the 20:00 dose as usual
• Both should skip the missed dose, because less than six hours remain
• Both should take two tablets together at 20:00
• Dabigatran: take it now. Apixaban: skip it
• Both should take the missed dose now, then the 20:00 dose as usual

2Which symptom should prompt a patient on a DOAC to seek urgent, same-day care?

• Slightly heavier periods
• Bruising more easily than before
• Black, tarry stools
• A small cut that bleeds a little longer
• An occasional brief nosebleed

3On day 5 of rivaroxaban 15 mg twice daily for a DVT, a patient realises at 20:00, when her evening dose is due, that she missed the morning dose. What should she do?

• Take the missed tablet tomorrow morning as well as the usual dose
• Skip both today’s doses and restart tomorrow
• Take one tablet now and forget the missed dose
• Take three tablets now
• Take two 15 mg tablets now, to make up the 30 mg for that day, then continue twice daily tomorrow

4A 32-year-old woman on rivaroxaban for VTE has very heavy periods and is thinking of stopping her tablets. Which approach is described in the animation?

• Reassure her that it is expected and needs no action
• Ask about it directly, and consider tranexamic acid, hormonal treatment (oestrogen-containing contraception is acceptable while she is anticoagulated), or a change of agent such as apixaban or dabigatran
• Add aspirin to reduce clot risk while her periods are heavy
• Halve the rivaroxaban dose
• Stop anticoagulation, as heavy periods are a contraindication

5Which advice about painkillers bought over the counter is correct for a patient on a DOAC?

• Aspirin is the safest choice
• Diclofenac is preferred because it has no effect on platelets
• Ibuprofen is safe if taken with food
• Paracetamol is fine; do not buy ibuprofen or aspirin over the counter, and check with the pharmacist if in doubt
• Naproxen is safe because it is only taken twice a day

1A 74-year-old man on dabigatran 150 mg twice daily for atrial fibrillation falls and is brought in with a large intracerebral haemorrhage and a GCS of 11. His last dose was four hours ago and his creatinine clearance is 45 mL/min. After resuscitation, what is the most appropriate specific treatment?

• Four-factor prothrombin complex concentrate 50 units/kg
• Idarucizumab 5 g intravenously
• Prothrombin complex concentrate, because dabigatran has no specific antidote
• Urgent haemodialysis as the first-line measure
• Andexanet alfa by bolus and infusion

2A patient on a DOAC arrives with major bleeding. Which single piece of history does the animation say tells you most?

• The date it was started
• The last INR
• The last haemoglobin
• The indication for the DOAC
• The time of the last dose

3A patient on dabigatran has a normal thrombin time. What does this tell you?

• The patient is taking apixaban, not dabigatran
• Nothing — the thrombin time is insensitive to dabigatran
• A clinically relevant dabigatran level is effectively excluded
• Idarucizumab is still required before surgery
• The patient has a supratherapeutic level

4According to NICE (TA697), for which situation is andexanet alfa recommended?

• Life-threatening or uncontrolled gastrointestinal bleeding on apixaban or rivaroxaban
• Reversal before elective surgery
• Intracranial haemorrhage on apixaban or rivaroxaban
• Reversal of dabigatran
• Any bleeding on edoxaban

5A patient with atrial fibrillation has a gastrointestinal bleed on apixaban; the source is secured endoscopically. When does the animation suggest restarting anticoagulation?

• Never — a major bleed means stopping for good
• Within 24 hours of the endoscopy
• After three months
• At around a week, earlier if thrombotic risk is high
• After four to eight weeks, following an MDT decision

1A 72-year-old woman with atrial fibrillation takes rivaroxaban 20 mg once daily. Her creatinine clearance is 70 mL/min. She is listed for an elective total knee replacement under general anaesthesia on a Thursday morning. What is the correct plan?

• Last dose on the Monday, no bridging, restart 48–72 hours after surgery once haemostasis is secure
• Last dose on the Saturday, giving five clear days as for warfarin
• Last dose on the Monday, bridge with treatment-dose low molecular weight heparin until the morning of surgery
• Continue rivaroxaban throughout, as knee replacement is a low bleeding risk procedure
• Last dose on the Wednesday, no bridging, restart on the evening of surgery

2A patient on apixaban needs a single dental extraction. What does the animation advise?

• Switch to warfarin for the procedure
• Stop apixaban for 2 days before
• Stop apixaban for 5 days and bridge with LMWH
• Continue apixaban without interruption and achieve haemostasis with local measures
• Give a reversal agent before the extraction

3A patient on apixaban with normal renal function is listed for a short, uncomplicated laparoscopic inguinal hernia repair under general anaesthesia, expected to take under 45 minutes, on a Thursday. When is the last dose?

• Wednesday
• Tuesday, leaving one full drug-free day
• The previous Saturday
• Monday, leaving two drug-free days
• No interruption is needed

4A patient on dabigatran with a creatinine clearance of 40 mL/min is listed for major abdominal surgery. According to the CHEST schedule, what changes compared with the standard high-risk schedule?

• Nothing — renal function does not change the schedule
• Add one day — the last dose is four days before
• Bridge with treatment-dose LMWH
• Shorten it, because dabigatran is dialysable
• Add two days — the last dose is five days before

5A patient had an epidural catheter for postoperative analgesia. When can the DOAC be restarted?

• Immediately after the catheter is removed
• Only after 7 days
• Not while the catheter is in place; a low dose about 8 hours after removal, and a high dose about 24 hours after (or later if the surgery requires)
• At any time, as epidurals do not affect DOAC timing
• While the catheter is in, at half dose