A 28-year-old woman presents with a 3-day history of dysuria, urinary frequency, and suprapubic pain. She is otherwise well with no fever. Urine dipstick shows nitrites positive, leucocytes positive. What is the most appropriate first-line antibiotic treatment?

Trimethoprim 200mg BD for 3 days

Amoxicillin 500mg TDS for 7 days

Ciprofloxacin 500mg BD for 7 days

Nitrofurantoin 50mg QDS for 3 days

Co-amoxiclav 625mg TDS for 7 days

A 59-year-old man with type 1 diabetes for 25 years is admitted with acute pancreatitis. His usual insulin regimen is insulin glargine 32 units at bedtime and insulin lispro 8 units with meals. He is kept nil by mouth and started on intravenous fluids. His admission glucose is 16.2 mmol/L. According to best practice for managing insulin in acute illness with nil-by-mouth status, what is the most appropriate insulin management?

Continue insulin glargine at usual dose; omit insulin lispro while nil by mouth

Continue insulin glargine; give insulin lispro based on blood glucose readings every 4 hours

Stop all insulin until he is eating and drinking again

Convert to variable-rate intravenous insulin infusion at 0.05 units/kg/hour

Give half the usual total daily insulin dose as basal insulin only

A 68-year-old woman with non-valvular atrial fibrillation (CHA₂DS₂-VASc score 4) is on apixaban 5mg twice daily. She is diagnosed with intermediate-risk myelodysplastic syndrome requiring treatment with azacitidine chemotherapy, which carries significant thrombocytopenia risk (expected platelet nadir 20-50 × 10⁹/L). What is the most appropriate anticoagulation strategy during chemotherapy?

Temporarily stop all anticoagulation during chemotherapy cycles; restart when platelets >50 × 10⁹/L

Continue apixaban 5mg twice daily throughout chemotherapy; monitor platelets weekly

Reduce apixaban to 2.5mg twice daily during chemotherapy cycles

Switch to prophylactic-dose LMWH during chemotherapy cycles

Switch to warfarin with target INR 2-3 as it can be more easily reversed

A 55-year-old woman with type 2 diabetes is on insulin detemir 38 units at 22:00 and metformin 1g twice daily. Her blood glucose readings show: fasting 6-8 mmol/L, pre-lunch 12-15 mmol/L, pre-dinner 10-13 mmol/L, bedtime 8-10 mmol/L. HbA1c is 68 mmol/mol (8.4%). Understanding insulin pharmacodynamics, what is the most appropriate next step in optimizing her insulin regimen?

Add prandial rapid-acting insulin with main meals

Split insulin detemir to twice-daily dosing (20 units morning, 20 units evening)

Increase insulin detemir to 44 units at 22:00

Switch from insulin detemir to insulin glargine

A 64-year-old man with atrial fibrillation is on rivaroxaban 20mg once daily. He requires emergency laparotomy for perforated diverticulitis within 2 hours. He took his last dose of rivaroxaban 8 hours ago. His renal function shows eGFR 58 ml/min/1.73m². Pre-operative blood tests show Hb 118 g/L. What is the most appropriate management of his anticoagulation?

Give 4-factor prothrombin complex concentrate 50 units/kg before surgery

Proceed to surgery; accept increased bleeding risk as surgery is life-saving

Give fresh frozen plasma 15 ml/kg before surgery

Delay surgery 12 hours to allow rivaroxaban clearance

Give tranexamic acid 1g IV before surgery

A 46-year-old man with type 1 diabetes for 20 years presents with a 3-month history of unpredictable blood glucose control despite good insulin adherence. He reports that his hypoglycaemic episodes now occur without warning symptoms. Investigations show HbA1c 58 mmol/mol (7.5%) but frequent hypoglycaemia on continuous glucose monitoring. What is the most appropriate modification to his insulin regimen?

Relax blood glucose targets and accept higher HbA1c to restore hypoglycaemia awareness

Switch to insulin pump therapy with continuous glucose monitoring

Increase overall insulin doses to improve HbA1c

Add acarbose to slow carbohydrate absorption

Switch from rapid-acting to regular insulin analogues

A 58-year-old woman with atrial fibrillation is on edoxaban 60mg once daily. She develops acute bacterial endocarditis affecting the mitral valve and requires valve replacement surgery in 48 hours. Current renal function shows eGFR 65 ml/min/1.73m². What is the most appropriate approach to managing her anticoagulation perioperatively?

Stop edoxaban now, give PCC for reversal, start warfarin post-operatively with LMWH bridge

Continue edoxaban until 24 hours before surgery, then restart 6 hours post-operatively

Stop edoxaban 48 hours before surgery, bridge with LMWH, restart edoxaban post-operatively

Stop edoxaban now, start intravenous heparin infusion, restart edoxaban post-operatively

Stop edoxaban now, no bridging required, restart edoxaban 24-48 hours post-operatively

A 52-year-old woman with type 2 diabetes is established on insulin glargine 42 units at bedtime and metformin 1g twice daily. She is about to commence treatment for latent tuberculosis with rifampicin 600mg daily for 3 months. What is the most important consideration regarding her diabetes management?

Rifampicin may increase insulin requirements significantly due to enzyme induction

Rifampicin has no effect on insulin requirements

Rifampicin may decrease insulin requirements due to improved insulin sensitivity

Metformin dose should be reduced due to interaction with rifampicin

Insulin glargine should be switched to NPH insulin due to rifampicin interaction

A 71-year-old man with mechanical mitral valve replacement is on warfarin (target INR 2.5-3.5). He requires urgent colonoscopy for suspected lower GI bleeding. His current INR is 3.2. The procedure is needed within 12 hours. What is the most appropriate management of his anticoagulation?

Give intravenous vitamin K 5mg and proceed when INR <1.5

Omit warfarin doses and proceed when INR <1.5

Give oral vitamin K 1-2mg and proceed when INR <1.5

Give prothrombin complex concentrate (PCC) and proceed immediately

Proceed with colonoscopy at current INR of 3.2

A 63-year-old man with type 1 diabetes is admitted with severe diabetic ketoacidosis (pH 7.08, ketones 5.2 mmol/L, glucose 28 mmol/L). He is commenced on a fixed-rate intravenous insulin infusion at 0.1 units/kg/hour and receives fluid resuscitation. After 4 hours, his glucose has fallen to 14 mmol/L but ketones remain at 4.8 mmol/L and pH is 7.15. What is the most appropriate next step in his insulin management?

Continue current insulin infusion rate and add 10% glucose infusion

Reduce insulin infusion rate to 0.05 units/kg/hour as glucose is improving

Stop insulin infusion and switch to subcutaneous basal-bolus regimen

Increase insulin infusion rate to 0.15 units/kg/hour to accelerate ketone clearance

Continue current insulin infusion without adding glucose

Anticoagulant safety - Free UK Medical PG Review

Quick Overview

Anticoagulant prescribing carries high risk of harm through bleeding or thrombosis. Safe use requires precise dosing based on renal function, systematic bleeding risk assessment, knowledge of reversal agents, and clear peri-procedural management. NICE NG196 emphasizes individualised therapy with regular monitoring and patient education.

Core Facts & Concepts

DOAC Dosing (Renal Adjustments)

Drug	Standard Dose	CrCl 30-50 ml/min	CrCl 15-30 ml/min	CrCl <15 ml/min
Apixaban	5mg BD	2.5mg BD if ≥2 criteria*	2.5mg BD	Avoid
Rivaroxaban	20mg OD	15mg OD	15mg OD	Avoid
Edoxaban	60mg OD	30mg OD	30mg OD	Avoid
Dabigatran	150mg BD	110mg BD	Avoid	Avoid

*Apixaban dose reduction criteria: Age ≥80 years, weight ≤60kg, creatinine ≥133 µmol/L

Warfarin Target INR

DVT/PE treatment: 2.5 (range 2.0-3.0)
Recurrent VTE on warfarin: 3.5 (range 3.0-4.0)
Mechanical heart valves: 2.5-3.5 (valve-dependent)

Figure 1: CT brain showing acute intracerebral haemorrhage with mass effect

HAS-BLED Score (Bleeding Risk)

Hypertension (SBP >160 mmHg): 1 point
Abnormal renal/liver function: 1 point each
Stroke history: 1 point
Bleeding history/predisposition: 1 point
Labile INR (TTR <60%): 1 point
Elderly (age >65): 1 point
Drugs/alcohol: 1 point each

Score ≥3 = HIGH RISK (requires closer monitoring, not contraindication)

Reversal Agents

💊 Warfarin: Vitamin K (IV 5-10mg) + Prothrombin Complex Concentrate (PCC) for major bleeding
💊 Dabigatran: Idarucizumab 5g IV (specific reversal)
💊 Xa inhibitors: Andexanet alfa 400-800mg IV OR PCC 50 units/kg
💊 All: Tranexamic acid 1g IV TDS as adjunct

⚠️ Warning: DOACs contraindicated in mechanical heart valves and antiphospholipid syndrome (warfarin only)

Problem-Solving Approach

Peri-Procedural Management (NICE NG196)

Classify bleeding risk of procedure
- Low risk: Continue anticoagulation (e.g., dental extraction, cataract surgery)
- High risk: Withhold anticoagulation (e.g., major surgery, spinal anaesthesia)
DOAC withholding times (high-risk procedures)
- CrCl ≥50: Omit 2 doses (BD drugs) or 24 hours (OD drugs)
- CrCl 30-50: Omit 3 doses (BD) or 48 hours (OD)
- CrCl 15-30: Omit 4 doses (BD) or 72 hours (OD)
Warfarin bridging (high thrombotic risk)
- Stop warfarin 5 days pre-procedure
- Check INR day before surgery (target <1.5)
- Bridge with therapeutic LMWH if high VTE/stroke risk
- Restart warfarin evening of surgery if haemostasis achieved

Figure 2: Blood film showing thrombocytopenia with large platelets

Major Bleeding Management

Stop anticoagulant immediately
ABC assessment, IV access, FBC/coagulation screen
Give reversal agent (see above)
Transfuse if Hb <70 g/L (target 70-90 g/L)
Involve haematology/surgery urgently

🚩 Red Flags: INR >8, intracranial bleeding, uncontrolled bleeding despite measures, platelets <50×10⁹/L

Analysis Framework

DOAC vs Warfarin Comparison

Feature	DOACs	Warfarin
Monitoring	None routine	Regular INR checks
Onset	1-4 hours	48-72 hours
Half-life	8-15 hours	36-48 hours
Renal excretion	27-80% (drug-dependent)	Minimal
Food interactions	None	Vitamin K foods
Reversal	Specific/PCC	Vitamin K + PCC
Cost	Higher	Lower
Compliance monitoring	Difficult	INR tracking

Critical Drug Interactions

🚫 Avoid with DOACs: Strong P-glycoprotein/CYP3A4 inhibitors (ketoconazole, dronedarone, verapamil)
🚫 Warfarin: Antibiotics (erythromycin, metronidazole), amiodarone, NSAIDs ↑ INR
⚠️ Antiplatelet + anticoagulant: Only if clear indication (e.g., ACS + AF) - increases bleeding risk 2-3 fold

Visual Aid

Renal Function Assessment

Calculate CrCl using Cockcroft-Gault equation for DOAC dosing
Recheck renal function annually (every 6 months if CrCl <60 ml/min)
Acute illness: Reassess renal function immediately

Key Points Summary

✓ HAS-BLED ≥3 = high bleeding risk requiring closer monitoring, NOT a contraindication to anticoagulation

✓ DOAC dosing: Reduce when CrCl <50 ml/min; avoid if <15 ml/min (apixaban/rivaroxaban 15-30 ml/min acceptable)

✓ Peri-procedural: Withhold DOACs for 2-4 doses depending on renal function; warfarin needs 5 days + INR <1.5

✓ Reversal agents: Idarucizumab for dabigatran, andexanet alfa/PCC for Xa inhibitors, vitamin K + PCC for warfarin

✓ Major bleeding: Stop drug, give reversal agent, transfuse if Hb <70 g/L, involve specialists urgently

✓ Avoid DOACs in mechanical valves, antiphospholipid syndrome, and with strong P-gp/CYP3A4 inhibitors

✓ Annual renal monitoring mandatory for DOACs; more frequent if CrCl <60 ml/min or acute illness