Safe Prescribing — MCQs

A 76-year-old man with non-valvular atrial fibrillation has a CHA₂DS₂-VASc score of 5 and HAS-BLED score of 4. He has a history of previous ischaemic stroke, chronic kidney disease stage 3b (eGFR 38 ml/min/1.73m²), hypertension, and previous gastrointestinal bleeding from gastric ulcer (successfully treated 2 years ago with no recurrence). He declines warfarin due to monitoring burden. Which direct oral anticoagulant (DOAC) regimen represents the most appropriate choice considering his risk factors?

Q124

A 41-year-old woman with type 1 diabetes is 16 weeks pregnant. She has been experiencing recurrent nocturnal hypoglycaemia (2-3 episodes per week with glucose <3.5 mmol/L at 03:00) despite adjusting her evening meal bolus. Her current regimen is insulin detemir 18 units at 22:00 and insulin aspart with meals (6-8 units per meal). Her fasting glucose is 4.2-5.1 mmol/L and HbA1c is 42 mmol/mol. What is the most appropriate adjustment to minimize nocturnal hypoglycaemia?

Q125

A 68-year-old man with mechanical aortic valve replacement on warfarin (target INR 2.5-3.5) is admitted with a large retroperitoneal haematoma. His INR is 7.8, haemoglobin 72 g/L (from 135 g/L two weeks ago), BP 95/60 mmHg, heart rate 108 bpm. He is not actively bleeding externally. What is the most appropriate immediate management of his anticoagulation?

Q126

A 73-year-old woman with type 2 diabetes is admitted with hospital-acquired pneumonia. She is on insulin detemir 36 units at bedtime and metformin 1g twice daily at home. On day 3 of admission, she is on a variable rate insulin infusion (VRIII) requiring 4 units/hour to maintain glucose 6-10 mmol/L. Her oral intake has improved. You plan to transition to subcutaneous insulin. What total daily insulin dose should be prescribed?

Q127

A 55-year-old man with atrial fibrillation on dabigatran 150mg twice daily requires emergency surgery for perforated diverticulitis within 2 hours. His last dose of dabigatran was 6 hours ago. His renal function is normal (eGFR 78 ml/min/1.73m²). Laboratory testing shows an elevated activated partial thromboplastin time (APTT). What is the most appropriate management of his anticoagulation?

Q128

A 67-year-old woman with type 1 diabetes for 35 years is admitted with pneumonia. Her blood glucose is managed with a variable rate insulin infusion (VRIII). She is now eating and drinking and ready to transition back to subcutaneous insulin. Her pre-admission regimen was insulin detemir 28 units twice daily and insulin aspart 8-10 units with meals. When should her VRIII be discontinued?

Q129

A 63-year-old man with deep vein thrombosis is on rivaroxaban 15mg twice daily for initial treatment. He has completed 21 days of therapy. His renal function shows creatinine clearance of 48 ml/min, weight 82kg. What is the most appropriate ongoing anticoagulation management?

Q130

A 49-year-old woman with type 2 diabetes is admitted for elective total knee replacement. She is on insulin glargine 40 units at bedtime and metformin 1g twice daily. Her HbA1c is 58 mmol/mol. Surgery is scheduled for 08:00. What is the most appropriate perioperative insulin management?

Safe Prescribing UK Medical PG Practice Questions and MCQs

Question 121: What is the recommended monitoring frequency for full blood count in a patient who has been stable on methotrexate for rheumatoid arthritis for 18 months?

A. Every 2-4 weeks
B. Every 1-2 months
C. Every 2-3 months (Correct Answer)
D. Every 6 months
E. Annually

Explanation: ***Every 2-3 months*** - For patients on a **stable dose** of methotrexate for more than 12 months, the standard monitoring interval for **full blood count (FBC)** and LFTs is every 2-3 months. - This frequency balances the need to detect late-onset **myelosuppression** or **hepatotoxicity** while reducing the burden of frequent testing on stable patients. *Every 2-4 weeks* - This intensive monitoring is typically reserved for the **initiation phase** or during **dose escalation** until the dose and bloods have been stable for 6 weeks. - It is not required for a patient who has been stable for 18 months, as the risk of acute adverse reactions is lower. *Every 1-2 months* - While safer than longer intervals, this is generally the transitional frequency once a dose is stable but before moving to **long-term maintenance monitoring**. - Current guidelines specifically recommend extending the interval to **12-weekly (3 months)** once clinical stability is established. *Every 6 months* - Monitoring every 6 months is considered unsafe for methotrexate because **bone marrow suppression** can occur unpredictably at any time during treatment. - Most guidelines mandate that the monitoring interval should **never exceed 3 months** for this high-risk DMARD. *Annually* - Annual monitoring is insufficient for detecting **cytopenias** or **liver enzyme elevations** associated with chronic methotrexate use. - Failure to monitor more frequently increases the risk of serious complications like **pancytopenia** or progressive **pulmonary toxicity** going unnoticed.

Question 122: A 58-year-old woman with inflammatory bowel disease is started on azathioprine 150mg daily. Which baseline investigation is essential before commencing this high-risk medication to identify patients at increased risk of myelosuppression?

A. Thiopurine methyltransferase (TPMT) activity (Correct Answer)
B. Glucose-6-phosphate dehydrogenase (G6PD) level
C. Serum immunoglobulin levels
D. HLA-B*5801 genotyping
E. Serum complement C3 and C4 levels

Explanation: ***Thiopurine methyltransferase (TPMT) activity*** - **TPMT** is the primary enzyme responsible for metabolizing thiopurine drugs; patients with low or absent activity are at a high risk of **life-threatening myelosuppression**. - Testing is essential to guide **dosage adjustments**, as those with intermediate activity require significant reduction, while those with deficiency should avoid the drug entirely. *Glucose-6-phosphate dehydrogenase (G6PD) level* - This test identifies risks for **hemolysis** when prescribing oxidative drugs such as **dapsone** or **primaquine**. - It does not relate to the metabolism of thiopurines or the risk of **bone marrow suppression** with azathioprine. *Serum immunoglobulin levels* - These are checked to identify **immunodeficiencies** but are not useful for predicting specific metabolic reactions to azathioprine. - Azathioprine may reduce levels over time, but baseline levels do not screen for **azathioprine toxicity**. *HLA-B*5801 genotyping* - This genetic screening is performed prior to starting **allopurinol** to identify patients at high risk for **Stevens-Johnson syndrome**. - While both drugs involve the purine pathway, this specific allele is not a marker for **azathioprine-induced leukopenia**. *Serum complement C3 and C4 levels* - Complement levels are used to monitor **disease activity** in autoimmune conditions like SLE, rather than drug metabolism. - They have no predictive value for **myelosuppression** or adverse reactions associated with thiopurine therapy.

Question 123: A 76-year-old man with non-valvular atrial fibrillation has a CHA₂DS₂-VASc score of 5 and HAS-BLED score of 4. He has a history of previous ischaemic stroke, chronic kidney disease stage 3b (eGFR 38 ml/min/1.73m²), hypertension, and previous gastrointestinal bleeding from gastric ulcer (successfully treated 2 years ago with no recurrence). He declines warfarin due to monitoring burden. Which direct oral anticoagulant (DOAC) regimen represents the most appropriate choice considering his risk factors?

A. Apixaban 5mg twice daily
B. Apixaban 2.5mg twice daily (Correct Answer)
C. Rivaroxaban 20mg once daily
D. Edoxaban 60mg once daily
E. Dabigatran 150mg twice daily

Explanation: ***Apixaban 2.5mg twice daily***- Dose reduction to **2.5mg twice daily** is indicated if the patient meets at least two of the three criteria: **age ≥80**, **weight ≤60kg**, or **serum creatinine ≥133 µmol/L**; in clinical practice, patients with high bleeding risk (**HAS-BLED 4**) and low **eGFR** often benefit from this reduced dose.- Apixaban is frequently the preferred **DOAC** in patients with a history of **gastrointestinal bleeding**, as it has demonstrated a superior safety profile regarding major bleeding compared to other agents.*Apixaban 5mg twice daily*- This is the standard dose for **non-valvular atrial fibrillation**, but it may be inappropriate for a patient with a high **HAS-BLED score** and impaired renal function.- Using the full dose in a patient with a significantly elevated stroke and bleeding risk requires careful balancing, and reduction is often prioritized when **renal impairment** (eGFR 38) is present.*Rivaroxaban 20mg once daily*- The standard 20mg dose is inappropriate here because **Rivaroxaban** requires dose reduction to **15mg once daily** when the **eGFR** falls between 15-49 ml/min.- **Rivaroxaban** has been associated with a higher risk of **GI bleeding** compared to apixaban, making it less suitable for this specific patient history.*Edoxaban 60mg once daily*- Similar to rivaroxaban, **Edoxaban** requires a dose reduction to **30mg once daily** for patients with a **CrCl** between 15-50 ml/min or a body weight ≤60kg.- The 60mg dose would pose an unacceptably high risk of bleeding in a patient with **Stage 3b Chronic Kidney Disease**.*Dabigatran 150mg twice daily*- **Dabigatran** is heavily dependent on **renal excretion**, and the 150mg dose is generally avoided or used with extreme caution in moderate renal impairment.- It is specifically noted for causing a higher incidence of **gastrointestinal side effects** and bleeding, which is contraindicated by this patient's history of a **gastric ulcer**.

Question 124: A 41-year-old woman with type 1 diabetes is 16 weeks pregnant. She has been experiencing recurrent nocturnal hypoglycaemia (2-3 episodes per week with glucose <3.5 mmol/L at 03:00) despite adjusting her evening meal bolus. Her current regimen is insulin detemir 18 units at 22:00 and insulin aspart with meals (6-8 units per meal). Her fasting glucose is 4.2-5.1 mmol/L and HbA1c is 42 mmol/mol. What is the most appropriate adjustment to minimize nocturnal hypoglycaemia?

A. Reduce insulin detemir dose to 14 units at 22:00
B. Split insulin detemir to 10 units at 08:00 and 10 units at 22:00 (Correct Answer)
C. Change the timing of insulin detemir from 22:00 to 08:00
D. Switch from insulin detemir to insulin glargine U300 for longer duration of action
E. Add a complex carbohydrate snack at bedtime without adjusting insulin

Explanation: ***Split insulin detemir to 10 units at 08:00 and 10 units at 22:00*** - **Insulin detemir** often has a duration of action of 12–20 hours; splitting the dose provides more **physiological basal coverage** and reduces the peak effect that occurs when a large single dose is given at night. - This approach addresses **nocturnal hypoglycaemia** (at 03:00) while ensuring adequate daytime basal insulin, which is critical for maintaining the tight **glycaemic control** required in pregnancy. *Reduce insulin detemir dose to 14 units at 22:00* - Simply reducing the dose may resolve the hypoglycemia but will likely lead to **fasting hyperglycaemia**, as the current fasting levels (4.2–5.1 mmol/L) are already at the lower end of the target range. - In **pregnancy**, avoiding both hypoglycemia and hyperglycemia is essential; a simple reduction lacks the necessary **basal coverage** for the rest of the 24-hour cycle. *Change the timing of insulin detemir from 22:00 to 08:00* - Moving detemir to the morning only would leave the patient with no **basal insulin cover** overnight, significantly increasing the risk of **nocturnal hyperglycaemia** and ketosis. - Due to the shorter duration of action of detemir compared to other analogues, **once-daily morning dosing** is generally insufficient for Type 1 Diabetes management. *Switch from insulin detemir to insulin glargine U300 for longer duration of action* - **Insulin glargine U300** (Toujeo) is currently not licensed for use during **pregnancy**, and there is limited safety data compared to detemir or glargine U100. - Detemir and **glargine U100** are the preferred long-acting analogues in pregnancy due to extensive evidence supporting their **safety and efficacy**. *Add a complex carbohydrate snack at bedtime without adjusting insulin* - Adding a snack without adjusting insulin is an outdated strategy that can lead to unnecessary **weight gain** and suboptimal control of **morning glucose levels**. - This does not address the underlying **pharmacokinetic issue** of the insulin detemir peak causing the 03:00 hypoglycaemic episodes.

Question 125: A 68-year-old man with mechanical aortic valve replacement on warfarin (target INR 2.5-3.5) is admitted with a large retroperitoneal haematoma. His INR is 7.8, haemoglobin 72 g/L (from 135 g/L two weeks ago), BP 95/60 mmHg, heart rate 108 bpm. He is not actively bleeding externally. What is the most appropriate immediate management of his anticoagulation?

A. Withhold warfarin and give oral vitamin K 5mg, repeat INR in 24 hours
B. Withhold warfarin and give intravenous vitamin K 5mg by slow infusion, repeat INR in 6 hours
C. Give intravenous vitamin K 5-10mg by slow infusion and four-factor prothrombin complex concentrate (PCC) 25-50 units/kg immediately (Correct Answer)
D. Give fresh frozen plasma 4 units and intravenous vitamin K 10mg immediately
E. Withhold warfarin only and monitor, as INR will normalize within 48 hours

Explanation: ***Give intravenous vitamin K 5-10mg by slow infusion and four-factor prothrombin complex concentrate (PCC) 25-50 units/kg immediately*** - This patient has **major, life-threatening bleeding** (retroperitoneal haematoma with significant blood loss and **hemodynamic instability** due to a critically high INR of 7.8). - **Four-factor PCC** provides immediate replacement of **vitamin K-dependent clotting factors (II, VII, IX, X)**, rapidly normalizing INR, while **intravenous vitamin K** ensures sustained new factor synthesis, preventing recurrence. *Withhold warfarin and give oral vitamin K 5mg, repeat INR in 24 hours* - **Oral vitamin K** has a delayed onset of action (12-24 hours) and is unsuitable for **major, life-threatening bleeding** requiring immediate reversal. - Simply withholding warfarin and waiting 24 hours would allow the patient to continue bleeding internally, leading to further **hemodynamic deterioration** and potential death. *Withhold warfarin and give intravenous vitamin K 5mg by slow infusion, repeat INR in 6 hours* - While **intravenous vitamin K** acts faster than oral (onset 4-6 hours), it still takes too long for a patient with **active, life-threatening bleeding** and **hemodynamic instability**. - **Immediate factor replacement** with agents like PCC is crucial for rapid hemostasis in such critical situations. *Give fresh frozen plasma 4 units and intravenous vitamin K 10mg immediately* - **Fresh Frozen Plasma (FFP)** is considered second-line to PCC because it requires **large volumes**, carries a risk of **fluid overload**, and needs thawing and cross-matching, causing delays. - **PCC** is superior for rapid warfarin reversal as it provides a concentrated, small-volume source of **vitamin K-dependent factors** with a faster administration time. *Withhold warfarin only and monitor, as INR will normalize within 48 hours* - Withholding warfarin alone is appropriate for **supratherapeutic INR without bleeding** or minor bleeding, but entirely inadequate for **major hemorrhage**. - The patient's **hemodynamic instability** and severe drop in **haemoglobin** indicate a critical need for immediate and aggressive reversal to prevent further blood loss and stabilize their condition.

Question 126: A 73-year-old woman with type 2 diabetes is admitted with hospital-acquired pneumonia. She is on insulin detemir 36 units at bedtime and metformin 1g twice daily at home. On day 3 of admission, she is on a variable rate insulin infusion (VRIII) requiring 4 units/hour to maintain glucose 6-10 mmol/L. Her oral intake has improved. You plan to transition to subcutaneous insulin. What total daily insulin dose should be prescribed?

A. 36 units total daily dose (same as her home insulin)
B. 50 units total daily dose (based on average requirement over 12 hours)
C. 72 units total daily dose (based on 24-hour VRIII requirement) (Correct Answer)
D. 96 units total daily dose (24-hour requirement plus 30% for stress)
E. 90 units total daily dose (24-hour requirement plus 25% safety margin)

Explanation: ***72 units total daily dose (based on 24-hour VRIII requirement)***- When transitioning from a **Variable Rate Insulin Infusion (VRIII)** to subcutaneous insulin, the total daily dose is typically estimated at 75-80% of the previous **24-hour VRIII requirement**.- In this case, 4 units/hour over 24 hours equals 96 units; 75% of this is **72 units**, which prudently accounts for the anticipated decrease in **insulin resistance** as the patient recovers from pneumonia and her acute illness. *36 units total daily dose (same as her home insulin)*- The patient's **home insulin dose** is insufficient during acute illness, as stress from hospital-acquired pneumonia significantly increases **insulin requirements** and resistance.- Her current need for 4 units/hour on VRIII (96 units/day) clearly indicates that her insulin demand is substantially higher than her usual **basal insulin** dose. *50 units total daily dose (based on average requirement over 12 hours)*- Calculating the total daily insulin dose based on only a **12-hour average** is inaccurate and can lead to significant under- or over-dosing, as insulin needs fluctuate over a full 24-hour period.- A **24-hour profile** is essential to accurately capture both **basal and prandial insulin** requirements for a safe and effective transition. *96 units total daily dose (24-hour requirement plus 30% for stress)*- Prescribing 100% of the VRIII dose (96 units) plus an additional 30% is dangerous and inappropriate when a patient is recovering from **acute illness**.- As the patient's condition improves and her oral intake is better, her **stress-induced insulin resistance** will decrease, making this dose highly likely to cause **hypoglycemia**. *90 units total daily dose (24-hour requirement plus 25% safety margin)*- Adding a

Question 127: A 55-year-old man with atrial fibrillation on dabigatran 150mg twice daily requires emergency surgery for perforated diverticulitis within 2 hours. His last dose of dabigatran was 6 hours ago. His renal function is normal (eGFR 78 ml/min/1.73m²). Laboratory testing shows an elevated activated partial thromboplastin time (APTT). What is the most appropriate management of his anticoagulation?

A. Proceed with surgery immediately without reversal agent as 6 hours have elapsed
B. Administer vitamin K 10mg intravenously and proceed with surgery in 30 minutes
C. Administer prothrombin complex concentrate (PCC) and proceed with surgery
D. Administer idarucizumab 5g intravenously and proceed with surgery when haemostasis is confirmed (Correct Answer)
E. Wait for another 6 hours (12 hours total) before proceeding with surgery to allow natural clearance

Explanation: ***Administer idarucizumab 5g intravenously and proceed with surgery when haemostasis is confirmed*** - **Idarucizumab** is a specific monoclonal antibody fragment used for the **rapid reversal** of the direct thrombin inhibitor **dabigatran** in cases of life-threatening bleeding or emergency surgery. - The standard dose is **5g IV** (two 2.5g vials), which provides immediate and sustained reversal, necessary here as the patient has significant anticoagulant activity (**elevated APTT**) and requires surgery within 2 hours. *Proceed with surgery immediately without reversal agent as 6 hours have elapsed* - **Dabigatran** has a half-life of **12–14 hours** in patients with normal renal function; therefore, significant levels remain in the system 6 hours after the last dose. - Moving forward without reversal in the setting of **perforated diverticulitis** carries a high risk of life-threatening **intraoperative hemorrhage**. *Administer vitamin K 10mg intravenously and proceed with surgery in 30 minutes* - **Vitamin K** is used specifically to reverse the effects of **warfarin** by facilitating the synthesis of clotting factors II, VII, IX, and X. - It has no effect on **dabigatran**, which works by directly inhibiting **thrombin** (Factor IIa), making this treatment ineffective in this scenario. *Administer prothrombin complex concentrate (PCC) and proceed with surgery* - **PCC** is a non-specific reversal agent primarily used for factor-depleting anticoagulants and can be considered for **Factor Xa inhibitors** if specific agents are unavailable. - Because **idarucizumab** is the specific, high-affinity antidote for **dabigatran**, it is the gold standard and preferred over non-specific PCC. *Wait for another 6 hours (12 hours total) before proceeding with surgery to allow natural clearance* - Waiting for natural clearance would delay the treatment of **perforated diverticulitis**, a surgical emergency that can lead to **sepsis** and death if not treated urgently. - Even at 12 hours post-dose, **therapeutic drug levels** may still be present, especially given the seriousness of the planned abdominal procedure.

Question 128: A 67-year-old woman with type 1 diabetes for 35 years is admitted with pneumonia. Her blood glucose is managed with a variable rate insulin infusion (VRIII). She is now eating and drinking and ready to transition back to subcutaneous insulin. Her pre-admission regimen was insulin detemir 28 units twice daily and insulin aspart 8-10 units with meals. When should her VRIII be discontinued?

A. Immediately after giving the first dose of subcutaneous rapid-acting insulin
B. 30 minutes after giving subcutaneous rapid-acting insulin
C. At least 30-60 minutes after giving long-acting insulin and with the first meal and rapid-acting insulin (Correct Answer)
D. 2 hours after giving the first dose of long-acting insulin
E. Once blood glucose is stable below 10 mmol/L for 4 hours

Explanation: ***At least 30-60 minutes after giving long-acting insulin and with the first meal and rapid-acting insulin***- To prevent **rebound hyperglycemia** or **ketosis**, a **variable rate insulin infusion (VRIII)** must overlap with subcutaneous insulin until the latter has reached therapeutic systemic levels.- Disconnecting the infusion 30-60 minutes after **basal insulin** (detemir) and concurrently with a **mealtime bolus** (aspart) ensures a safe transition without a gap in insulin coverage, which is critical in Type 1 diabetes.*Immediately after giving the first dose of subcutaneous rapid-acting insulin*- Subcutaneous **rapid-acting insulin** takes approximately 15-20 minutes to start working and longer to peak, leaving a dangerous window of inadequate insulin if the VRIII is stopped immediately.- This approach fails to account for the necessary **basal insulin** overlap required to maintain stable background glucose levels, which is vital for preventing **ketoacidosis** in Type 1 diabetes.*30 minutes after giving subcutaneous rapid-acting insulin*- While this provides a short overlap for the bolus, it does not ensure that the **long-acting basal insulin** (detemir) has reached sufficient plasma concentrations.- Without adequate **basal insulin overlap**, patients with **Type 1 diabetes** are at significant risk of developing ketosis or **diabetic ketoacidosis** due to the very short half-life of intravenous insulin.*2 hours after giving the first dose of long-acting insulin*- While 2 hours ensures the **basal insulin** is active, VRIII transition should ideally be timed with a **meal** to allow the patient to resume their normal subcutaneous bolus regimen.- Keeping the VRIII running for 2 hours after basal insulin without coordinating with a meal and **rapid-acting insulin** increases the risk of **hypoglycemia** if the patient is not eating or if the basal dose is excessive.*Once blood glucose is stable below 10 mmol/L for 4 hours*- Metabolic stability (blood glucose below 10 mmol/L) is a prerequisite for initiating the transition, but it does not dictate the physical timing of **discontinuing the infusion** pump.- The transition must always be managed by ensuring **pharmacokinetic overlap** between IV and SC routes, ensuring continuous insulin supply regardless of how long the glucose has been stable.

Question 129: A 63-year-old man with deep vein thrombosis is on rivaroxaban 15mg twice daily for initial treatment. He has completed 21 days of therapy. His renal function shows creatinine clearance of 48 ml/min, weight 82kg. What is the most appropriate ongoing anticoagulation management?

A. Continue rivaroxaban 15mg twice daily for another 21 days then switch to 20mg once daily
B. Switch to rivaroxaban 20mg once daily for ongoing therapy (Correct Answer)
C. Switch to rivaroxaban 15mg once daily for ongoing therapy due to renal impairment
D. Switch to apixaban 2.5mg twice daily for ongoing therapy
E. Continue rivaroxaban 15mg twice daily indefinitely

Explanation: ***Switch to rivaroxaban 20mg once daily for ongoing therapy***- For the treatment of **DVT/PE**, the standard **rivaroxaban** regimen is **15mg twice daily** for the first **21 days**, followed by a transition to **20mg once daily** for maintenance phase.- Since the patient has completed his 21-day initial treatment and his **CrCl is 48 ml/min** (which is >30 ml/min), the full maintenance dose of **20mg once daily** is appropriate.*Continue rivaroxaban 15mg twice daily for another 21 days then switch to 20mg once daily*- The **initial treatment phase** with twice-daily dosing specifically lasts only **21 days**; extending this phase increases the **bleeding risk** unnecessarily.- There is no clinical indication for a 42-day loading period for **Deep Vein Thrombosis** management.*Switch to rivaroxaban 15mg once daily for ongoing therapy due to renal impairment*- **Rivaroxaban dose reduction** to 15mg once daily for maintenance is typically only indicated if the **Creatinine Clearance (CrCl)** is between **15-29 ml/min**.- With a **CrCl of 48 ml/min**, this patient does not meet the threshold for renal dose adjustment and should receive the standard **20mg dose**.*Switch to apixaban 2.5mg twice daily for ongoing therapy*- **Apixaban 2.5mg twice daily** is a secondary prevention (prophylactic) dose used only after **6 months** of full-dose anticoagulant treatment.- This patient requires ongoing **treatment-dose anticoagulation**; switching to a low-dose prophylactic regimen at 3 weeks would be **sub-therapeutic** for an acute DVT.*Continue rivaroxaban 15mg twice daily indefinitely*- Continuing a **twice-daily loading regimen** indefinitely is not the licensed protocol and significantly increases the risk of **major hemorrhage**.- Stable maintenance therapy for DVT requires transitioning to **once-daily dosing** to ensure patient compliance and safety profile.

Question 130: A 49-year-old woman with type 2 diabetes is admitted for elective total knee replacement. She is on insulin glargine 40 units at bedtime and metformin 1g twice daily. Her HbA1c is 58 mmol/mol. Surgery is scheduled for 08:00. What is the most appropriate perioperative insulin management?

A. Omit morning metformin, give 80% of usual glargine dose on morning of surgery, start variable rate insulin infusion (Correct Answer)
B. Omit morning metformin, omit glargine, start variable rate insulin infusion on morning of surgery
C. Continue metformin and glargine as normal, start variable rate insulin infusion in addition
D. Omit morning metformin, give 100% of usual glargine dose on morning of surgery, no variable rate insulin infusion needed
E. Omit morning metformin, give 80% of usual glargine dose on morning of surgery, no variable rate insulin infusion needed

Explanation: ***Omit morning metformin, give 80% of usual glargine dose on morning of surgery, start variable rate insulin infusion*** - For elective surgery, **metformin** is omitted on the morning of surgery to minimize risks associated with fasting and potential renal impairment. - Administering **80% of basal insulin** (glargine) provides essential background coverage to prevent **ketosis**, while a **Variable Rate Intravenous Insulin Infusion (VRIII)** ensures precise glucose control during the perioperative fasting period. *Omit morning metformin, omit glargine, start variable rate insulin infusion on morning of surgery* - Completely omitting **glargine** is inappropriate as it can lead to **hyperglycemia** and a lack of baseline insulin coverage, increasing the risk of metabolic instability. - Even with a **VRIII**, maintaining a portion of the **basal insulin** helps stabilize blood glucose levels during the transition back to subcutaneous regimens. *Continue metformin and glargine as normal, start variable rate insulin infusion in addition* - Continuing **metformin** while fasting for surgery is avoided due to the potential risk of **lactic acidosis** if renal perfusion is compromised. - Giving **100% of the glargine dose** while the patient is nil-by-mouth (NBM) significantly increases the risk of **hypoglycemia**. *Omit morning metformin, give 100% of usual glargine dose on morning of surgery, no variable rate insulin infusion needed* - A full dose of **glargine** without oral intake is unsafe and likely to cause **hypoglycemia** during or after the procedure. - In major surgery (like a knee replacement), a **VRIII** is typically required to manage the metabolic stress response and maintain strict **glycaemic control**. *Omit morning metformin, give 80% of usual glargine dose on morning of surgery, no variable rate insulin infusion needed* - While the reduction in **glargine** is correct, omitting the **VRIII** for a major procedure where the patient is NBM ignores the need for active glucose management. - **VRIII** is the standard tier of care for insulin-dependent patients undergoing major surgery to prevent intraoperative **hyperglycemic** fluctuations.

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