Safe Prescribing — MCQs
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A 56-year-old woman with type 2 diabetes is admitted with severe community-acquired pneumonia requiring ICU admission. She is on insulin glargine 40 units at bedtime and metformin 1g twice daily at home. She is intubated and ventilated, receiving vasopressor support. Her capillary blood glucose is 18.4 mmol/L. What is the most appropriate diabetes management strategy?
A 48-year-old woman with severe psoriasis is started on methotrexate 15mg once weekly. She is counselled about the importance of folic acid supplementation. Which explanation best describes the rationale for folic acid co-prescription with methotrexate?
A 63-year-old woman with atrial fibrillation is established on rivaroxaban 20mg once daily. She develops cellulitis requiring hospital admission and intravenous antibiotics. Her renal function shows: creatinine 145 μmol/L, eGFR 38 ml/min/1.73m². Which statement best describes the appropriate management of her anticoagulation?
A 55-year-old man with type 2 diabetes is prescribed insulin detemir. According to the British National Formulary, what is the typical time to onset of action for insulin detemir after subcutaneous injection?
A 81-year-old woman with atrial fibrillation (CHA₂DS₂-VASc score 6) has been on apixaban 2.5mg twice daily for 2 years. She now develops stage 4 chronic kidney disease with eGFR declining from 48 ml/min/1.73m² to 24 ml/min/1.73m² over 6 months. She weighs 64kg and is aged 81 years. Her serum creatinine is 198 μmol/L. She has no recent bleeding and takes no interacting medications. What is the most appropriate management of her anticoagulation?
A 49-year-old woman with type 2 diabetes is established on insulin detemir 26 units twice daily (morning and bedtime) and metformin 1g twice daily. Her home blood glucose monitoring shows: fasting 6-8 mmol/L, pre-lunch 5-7 mmol/L, pre-dinner 12-15 mmol/L, bedtime 8-10 mmol/L. Her HbA1c is 64 mmol/mol. She is keen to optimize her diabetes control. What is the most appropriate modification to her treatment regimen?
A 67-year-old man with non-valvular atrial fibrillation (CHA₂DS₂-VASc score 4) has been on rivaroxaban 20mg once daily for 18 months. He now presents with biopsy-proven hepatocellular carcinoma and is being considered for transarterial chemoembolization (TACE). His baseline liver function shows: bilirubin 42 μmol/L, ALT 128 U/L, ALP 245 U/L, albumin 32 g/L, INR 1.4. His renal function is normal (eGFR 74 ml/min/1.73m²). What is the most appropriate anticoagulation strategy for this patient?
A 54-year-old woman with type 1 diabetes for 32 years presents with a 6-month history of frequent hypoglycaemic episodes without warning symptoms. She is on insulin degludec 28 units once daily and insulin aspart using carbohydrate counting. Her HbA1c is 48 mmol/mol. Continuous glucose monitoring reveals multiple episodes of glucose <3.0 mmol/L, including nocturnal episodes. She has normal renal function and no evidence of gastroparesis. What is the most important factor contributing to her impaired hypoglycaemia awareness?
A 72-year-old man with mechanical mitral valve replacement is established on warfarin with target INR 2.5-3.5. He is diagnosed with a new deep vein thrombosis and his current INR is 2.2. He has eGFR of 58 ml/min/1.73m² and weighs 82kg. What is the most appropriate management of his anticoagulation for the acute DVT?
A 59-year-old man with type 2 diabetes is on basal-bolus insulin therapy (insulin glargine 36 units at bedtime and insulin aspart 12 units three times daily before meals). He reports recurrent hypoglycaemic episodes between 3-4 AM, with blood glucose readings of 2.8-3.2 mmol/L on multiple occasions. His bedtime glucose readings are typically 8-10 mmol/L and his pre-lunch and pre-dinner readings are well controlled at 5-7 mmol/L. What is the most appropriate modification to his insulin regimen?
Safe Prescribing UK Medical PG Practice Questions and MCQs
Question 61: A 56-year-old woman with type 2 diabetes is admitted with severe community-acquired pneumonia requiring ICU admission. She is on insulin glargine 40 units at bedtime and metformin 1g twice daily at home. She is intubated and ventilated, receiving vasopressor support. Her capillary blood glucose is 18.4 mmol/L. What is the most appropriate diabetes management strategy?
- A. Continue insulin glargine 40 units daily via nasogastric tube and start intravenous insulin infusion to target glucose 6-10 mmol/L
- B. Commence variable rate intravenous insulin infusion targeting glucose 6-10 mmol/L, discontinue all other glucose-lowering medications (Correct Answer)
- C. Increase insulin glargine to 50 units daily, add rapid-acting insulin correction doses every 4 hours as needed
- D. Start sliding scale subcutaneous insulin four times daily, withhold insulin glargine and metformin until extubated
- E. Continue insulin glargine at current dose, restart metformin via nasogastric tube, add intravenous insulin as needed
Explanation: ***Commence variable rate intravenous insulin infusion targeting glucose 6-10 mmol/L, discontinue all other glucose-lowering medications*** - For **critically ill patients** (intubated and on vasopressors), a **variable rate intravenous insulin infusion (VRIII)** is the gold standard as it allows for rapid titration against fluctuating insulin resistance. - The recommended target blood glucose in the ICU is **6.0–10.0 mmol/L** to balance glycemic control while minimizing the significant risk of **hypoglycemia** associated with tighter targets. *Continue insulin glargine 40 units daily via nasogastric tube and start intravenous insulin infusion to target glucose 6-10 mmol/L* - **Insulin glargine** is a basal insulin intended for subcutaneous injection; it is not administered via a **nasogastric tube** because it is a protein that would be digested in the stomach. - When starting a **VRIII** in the acute ICU setting for Type 2 Diabetes, overlapping with subcutaneous basal insulin is generally avoided to prevent **unpredictable hypoglycemia** during hemodynamic instability. *Increase insulin glargine to 50 units daily, add rapid-acting insulin correction doses every 4 hours as needed* - Subcutaneous insulin absorption is highly **unreliable** in patients on **vasopressors** due to peripheral vasoconstriction and poor tissue perfusion. - Relying on intermittent correction doses (reactive management) leads to poor glycemic stability compared to the proactive, continuous titration provided by **intravenous infusion**. *Start sliding scale subcutaneous insulin four times daily, withhold insulin glargine and metformin until extubated* - **Sliding scale insulin (SSI)** alone is widely discouraged in clinical practice as it treats hyperglycemia after it occurs rather than preventing it, leading to poor control. - In the context of **shock and multiorgan failure**, intravenous delivery is mandatory to ensure the medication reaches the systemic circulation effectively. *Continue insulin glargine at current dose, restart metformin via nasogastric tube, add intravenous insulin as needed* - **Metformin** must be discontinued in critically ill patients due to the high risk of **lactic acidosis**, especially in those with potential renal impairment or tissue hypoxia. - Continuing **subcutaneous glargine** while simultaneously adding an IV infusion complicates the management and increases the risk of **dose stacking** and hypoglycemia.
Question 62: A 48-year-old woman with severe psoriasis is started on methotrexate 15mg once weekly. She is counselled about the importance of folic acid supplementation. Which explanation best describes the rationale for folic acid co-prescription with methotrexate?
- A. Folic acid enhances the immunosuppressive effects of methotrexate by potentiating dihydrofolate reductase inhibition
- B. Folic acid reduces methotrexate-related toxicity without significantly compromising its therapeutic efficacy (Correct Answer)
- C. Folic acid is required to prevent megaloblastic anaemia caused by methotrexate-induced vitamin B12 deficiency
- D. Folic acid increases methotrexate absorption from the gastrointestinal tract, improving bioavailability
- E. Folic acid accelerates methotrexate metabolism and renal excretion, reducing plasma drug levels
Explanation: ***Folic acid reduces methotrexate-related toxicity without significantly compromising its therapeutic efficacy*** - **Methotrexate** is a folate antagonist that inhibits **dihydrofolate reductase (DHFR)**, impairing DNA synthesis in rapidly dividing cells, which is the basis of its therapeutic effect but also causes significant side effects. - **Folic acid supplementation** provides a substrate for normal folate pathways in non-target cells, thereby mitigating common toxicities like **mucositis**, **bone marrow suppression**, and **hepatotoxicity**, without negating the anti-inflammatory or anti-proliferative effects against psoriasis. *Folic acid enhances the immunosuppressive effects of methotrexate by potentiating dihydrofolate reductase inhibition* - Folic acid acts as a **substrate** in the folate pathway and does not enhance or potentiate the inhibitory effect of methotrexate on DHFR. - The purpose of co-prescription is to **counteract**, not augment, methotrexate's mechanism, specifically in healthy cells. *Folic acid is required to prevent megaloblastic anaemia caused by methotrexate-induced vitamin B12 deficiency* - Methotrexate primarily interferes with **folate metabolism**, leading to functional folate deficiency and potentially **macrocytic anemia** (which resembles megaloblastic anemia). - It does not directly cause or address a deficiency in **vitamin B12**, which is involved in a separate but interconnected metabolic pathway. *Folic acid increases methotrexate absorption from the gastrointestinal tract, improving bioavailability* - There is no evidence that folic acid improves the **gastrointestinal absorption** or **bioavailability** of methotrexate. - In fact, patients are often advised to take folic acid at least **24 hours after** their weekly methotrexate dose to avoid potential competitive absorption or interaction at the cellular level. *Folic acid accelerates methotrexate metabolism and renal excretion, reducing plasma drug levels* - Folic acid does not significantly alter the **pharmacokinetics** of methotrexate, including its metabolism or **renal excretion**. - Its role is to provide a competitive substrate to protect healthy cells from the **antifolate effects** of methotrexate, not to directly reduce systemic drug levels.
Question 63: A 63-year-old woman with atrial fibrillation is established on rivaroxaban 20mg once daily. She develops cellulitis requiring hospital admission and intravenous antibiotics. Her renal function shows: creatinine 145 μmol/L, eGFR 38 ml/min/1.73m². Which statement best describes the appropriate management of her anticoagulation?
- A. Continue rivaroxaban 20mg once daily as the eGFR is above 30 ml/min/1.73m²
- B. Reduce rivaroxaban dose to 15mg once daily due to moderate renal impairment (Correct Answer)
- C. Switch to warfarin as DOACs are contraindicated in renal impairment
- D. Temporarily discontinue rivaroxaban until the acute infection resolves
- E. Increase monitoring but continue current dose as dosing is primarily based on indication
Explanation: ***Reduce rivaroxaban dose to 15mg once daily due to moderate renal impairment*** - For stroke prevention in **atrial fibrillation**, the standard dose of **rivaroxaban** is reduced from 20mg to **15mg once daily** when the **eGFR** falls between **15-49 ml/min/1.73m²**. - This patient's **eGFR of 38 ml/min/1.73m²** falls directly into this range, necessitating a dose adjustment to prevent drug accumulation and mitigate the **risk of bleeding**. *Continue rivaroxaban 20mg once daily as the eGFR is above 30 ml/min/1.73m²* - The dose reduction threshold for rivaroxaban in **atrial fibrillation** is an **eGFR below 50 ml/min/1.73m²**, not 30 for continuation. - Continuing the full 20mg dose with an **eGFR of 38 ml/min/1.73m²** would lead to increased drug exposure and a higher **bleeding risk**. *Switch to warfarin as DOACs are contraindicated in renal impairment* - **Direct Oral Anticoagulants (DOACs)** like rivaroxaban are not contraindicated in all degrees of renal impairment; specific dose adjustments are made, and they are generally contraindicated only when **eGFR falls below 15 ml/min/1.73m²**. - Switching to **warfarin** would introduce additional complexities, such as the need for frequent **INR monitoring** and potential drug interactions, without clear clinical benefit over a dose-adjusted DOAC. *Temporarily discontinue rivaroxaban until the acute infection resolves* - While acute illness can transiently affect renal function, **cellulitis** itself is not an indication to discontinue anticoagulation for **atrial fibrillation**. - Discontinuing rivaroxaban would place the patient at a significantly increased risk of **thromboembolic events**, such as **stroke**, given their underlying condition. *Increase monitoring but continue current dose as dosing is primarily based on indication* - While the indication (**atrial fibrillation**) dictates the need for anticoagulation, **renal function** is a critical parameter that determines the appropriate dose for many drugs, including **rivaroxaban**. - Simply increasing monitoring without adjusting the dose, when guidelines clearly indicate a need for dose reduction based on **eGFR**, is insufficient and would not adequately address the increased **bleeding risk**.
Question 64: A 55-year-old man with type 2 diabetes is prescribed insulin detemir. According to the British National Formulary, what is the typical time to onset of action for insulin detemir after subcutaneous injection?
- A. 15 minutes
- B. 30 minutes
- C. 1-2 hours (Correct Answer)
- D. 4-6 hours
- E. 8-10 hours
Explanation: ***1-2 hours*** - **Insulin detemir** is a **long-acting basal insulin** analogue, designed to provide steady glucose control with a typical **onset of action** of **1 to 2 hours** after subcutaneous injection. - Its prolonged action is due to **reversible albumin binding** and **hexamer formation**, which delays absorption from the injection site. *15 minutes* - This onset time is characteristic of **rapid-acting insulin analogues** (e.g., **insulin aspart**, **lispro**, **glulisine**). - These insulins are typically administered immediately before or after meals to manage **postprandial glucose** excursions. *30 minutes* - This onset time is associated with **short-acting (soluble) insulins** (e.g., **Actrapid**, **Humulin S**). - They require administration approximately 20-30 minutes before a meal to allow their **peak effect** to coincide with food absorption. *4-6 hours* - An onset of **4-6 hours** is much slower than expected for **insulin detemir** and most basal insulins, which aim to provide earlier glucose lowering. - This timeframe is more reflective of the **duration of action** or peak for some **intermediate-acting insulins** rather than the onset for a basal insulin. *8-10 hours* - An onset of **8-10 hours** would be clinically inappropriate and dangerous, as it would leave a significant period of **uncontrolled hyperglycemia** after injection. - This timeframe far exceeds the typical onset of any commonly used insulin and is more aligned with the **duration** of some **long-acting insulins** rather than their initiation of effect.
Question 65: A 81-year-old woman with atrial fibrillation (CHA₂DS₂-VASc score 6) has been on apixaban 2.5mg twice daily for 2 years. She now develops stage 4 chronic kidney disease with eGFR declining from 48 ml/min/1.73m² to 24 ml/min/1.73m² over 6 months. She weighs 64kg and is aged 81 years. Her serum creatinine is 198 μmol/L. She has no recent bleeding and takes no interacting medications. What is the most appropriate management of her anticoagulation?
- A. Continue apixaban 2.5mg twice daily as she meets dose reduction criteria (Correct Answer)
- B. Increase apixaban to 5mg twice daily as eGFR >15 ml/min/1.73m²
- C. Switch to warfarin as DOACs are contraindicated with eGFR <30 ml/min/1.73m²
- D. Stop apixaban as risks outweigh benefits with severe renal impairment
- E. Reduce apixaban to 2.5mg once daily due to significant renal impairment
Explanation: ***Continue apixaban 2.5mg twice daily as she meets dose reduction criteria*** - Apixaban dose reduction from 5mg to **2.5mg twice daily** is indicated if a patient meets two out of three criteria: **age ≥80 years**, body **weight ≤60 kg**, or **serum creatinine ≥133 μmol/L**. - This patient, at 81 years and with a serum creatinine of 198 μmol/L, meets two criteria, confirming that her current dose of 2.5mg twice daily is the **correct renally-adjusted dose** for stroke prevention in atrial fibrillation. *Increase apixaban to 5mg twice daily as eGFR >15 ml/min/1.73m²* - Increasing the dose to 5mg twice daily would be inappropriate because the patient **meets criteria for dose reduction** based on age and serum creatinine, irrespective of her eGFR being >15 ml/min/1.73m². - The standard 5mg dose would significantly elevate the **risk of major bleeding** in this elderly patient with established stage 4 CKD. *Switch to warfarin as DOACs are contraindicated with eGFR <30 ml/min/1.73m²* - This statement is incorrect as apixaban is **not contraindicated** for eGFR between 15-29 ml/min/1.73m², and its use is supported down to an eGFR of 15 ml/min/1.73m². - While some DOACs, like **dabigatran**, have a stricter contraindication below 30 ml/min/1.73m², apixaban has a more favorable profile in patients with moderate to severe CKD compared to warfarin. *Stop apixaban as risks outweigh benefits with severe renal impairment* - With a **CHA₂DS₂-VASc score of 6**, the patient has a very high risk of **thromboembolic stroke**, meaning the benefits of appropriate anticoagulation generally outweigh the bleeding risk. - Anticoagulation with apixaban is typically continued until the **eGFR drops below 15 ml/min/1.73m²** or the patient progresses to end-stage renal disease, which is not the case here. *Reduce apixaban to 2.5mg once daily due to significant renal impairment* - Apixaban is only licensed for **twice-daily (BD) administration** for stroke prevention in atrial fibrillation; a once-daily regimen is not an approved dosing schedule. - Reducing to once-daily dosing would result in **sub-therapeutic drug levels**, significantly increasing the patient's risk of **ischemic stroke** due to inadequate anticoagulation.
Question 66: A 49-year-old woman with type 2 diabetes is established on insulin detemir 26 units twice daily (morning and bedtime) and metformin 1g twice daily. Her home blood glucose monitoring shows: fasting 6-8 mmol/L, pre-lunch 5-7 mmol/L, pre-dinner 12-15 mmol/L, bedtime 8-10 mmol/L. Her HbA1c is 64 mmol/mol. She is keen to optimize her diabetes control. What is the most appropriate modification to her treatment regimen?
- A. Increase both morning and evening insulin detemir doses by 10%
- B. Increase evening insulin detemir dose only by 4 units
- C. Add rapid-acting insulin before lunch (Correct Answer)
- D. Increase metformin to 1g three times daily
- E. Switch to basal-bolus regimen with once-daily basal insulin and rapid-acting insulin before each meal
Explanation: ***Add rapid-acting insulin before lunch*** - The patient's blood glucose is significantly elevated **pre-dinner (12-15 mmol/L)**, indicating **postprandial hyperglycemia** following the lunch meal that is not adequately covered by the current basal regimen. - Fasting and pre-lunch readings are within target (5-8 mmol/L), suggesting that the **twice-daily insulin detemir** provides adequate basal coverage, making a targeted **prandial insulin** addition the most appropriate next step. *Increase both morning and evening insulin detemir doses by 10%* - Increasing the morning detemir dose is unlikely to correct the **pre-dinner hyperglycemia** and could lead to **hypoglycemia** before lunch, as current pre-lunch levels are good. - Increasing the evening detemir dose would primarily lower **fasting glucose**, which is already near target, and risks **nocturnal hypoglycemia** without directly addressing the post-lunch spike. *Increase evening insulin detemir dose only by 4 units* - An increase in the evening basal insulin primarily affects **fasting glucose levels**, which are currently well-controlled (6-8 mmol/L). - This modification risks **hypoglycemia** during the night or early morning without correcting the significant **post-lunch/pre-dinner hyperglycemia**. *Increase metformin to 1g three times daily* - The patient is already on metformin 2g daily, which is often the **maximum effective dose**; increasing to 3g offers marginal additional benefit and significantly increases the risk of **gastrointestinal side effects**. - Metformin alone is generally insufficient to manage the significant **postprandial glucose excursion** observed in a patient already on basal insulin therapy. *Switch to basal-bolus regimen with once-daily basal insulin and rapid-acting insulin before each meal* - While a **full basal-bolus regimen** is a potential long-term goal for type 2 diabetes, it represents a more complex and intensive treatment step. - The current problem is a specific **post-lunch hyperglycemia**, which can be effectively managed with a **step-wise intensification** (adding one mealtime insulin dose) before escalating to a full regimen.
Question 67: A 67-year-old man with non-valvular atrial fibrillation (CHA₂DS₂-VASc score 4) has been on rivaroxaban 20mg once daily for 18 months. He now presents with biopsy-proven hepatocellular carcinoma and is being considered for transarterial chemoembolization (TACE). His baseline liver function shows: bilirubin 42 μmol/L, ALT 128 U/L, ALP 245 U/L, albumin 32 g/L, INR 1.4. His renal function is normal (eGFR 74 ml/min/1.73m²). What is the most appropriate anticoagulation strategy for this patient?
- A. Continue rivaroxaban 20mg once daily as hepatocellular carcinoma is not a contraindication to DOACs
- B. Reduce rivaroxaban to 15mg once daily due to hepatic impairment
- C. Switch to apixaban 2.5mg twice daily which is safer in liver disease
- D. Stop rivaroxaban and avoid anticoagulation due to high bleeding risk from liver disease and planned TACE (Correct Answer)
- E. Stop rivaroxaban and switch to warfarin with careful INR monitoring
Explanation: ***Stop rivaroxaban and avoid anticoagulation due to high bleeding risk from liver disease and planned TACE*** - The patient presents with significant **hepatic impairment**, characterized by elevated bilirubin (42 μmol/L), low albumin (32 g/L), and an elevated INR (1.4). These features indicate at least **Child-Pugh Class B** liver disease, which contraindicates the use of DOACs like rivaroxaban due to increased risk of bleeding. - The combination of **severe liver disease-associated coagulopathy** and the planned invasive procedure of **Transarterial Chemoembolization (TACE)** significantly elevates the risk of hemorrhage, making continued anticoagulation unsafe and outweighing its benefits for stroke prevention. *Continue rivaroxaban 20mg once daily as hepatocellular carcinoma is not a contraindication to DOACs* - While hepatocellular carcinoma itself isn't a direct contraindication for DOACs, the patient's **hepatic synthetic dysfunction** and resultant **coagulopathy** (INR 1.4) are critical contraindications for rivaroxaban. - **Rivaroxaban** relies significantly on hepatic metabolism, and its use is contraindicated in patients with **Child-Pugh Class B or C** liver disease due to unpredictable drug accumulation and heightened bleeding risk. *Reduce rivaroxaban to 15mg once daily due to hepatic impairment* - The dose adjustment of **rivaroxaban to 15mg** is primarily indicated for patients with moderate **renal impairment** (eGFR 15-49 ml/min), not for liver impairment. - There is no established evidence or guideline to support the safe and effective use of a reduced rivaroxaban dose in patients with **Child-Pugh B or C** liver disease, where it remains generally contraindicated. *Switch to apixaban 2.5mg twice daily which is safer in liver disease* - Although **apixaban** has a lesser degree of hepatic metabolism compared to rivaroxaban, all **DOACs** are contraindicated in severe liver disease (Child-Pugh C) and in **Child-Pugh B** patients with associated coagulopathy. - The 2.5mg twice daily dose of apixaban is typically reserved for specific criteria related to age, weight, or renal function, and is not a generalized strategy to manage significant **liver-induced bleeding risk** in cases where DOACs are otherwise contraindicated. *Stop rivaroxaban and switch to warfarin with careful INR monitoring* - Managing **warfarin** in patients with advanced liver disease is extremely challenging and often unsafe, as the underlying condition causes an **elevated baseline INR** due to impaired synthesis of clotting factors. - This makes **INR monitoring** unreliable for warfarin titration, leading to a high risk of both **thrombosis and hemorrhage** and making it an inappropriate choice in this patient's condition.
Question 68: A 54-year-old woman with type 1 diabetes for 32 years presents with a 6-month history of frequent hypoglycaemic episodes without warning symptoms. She is on insulin degludec 28 units once daily and insulin aspart using carbohydrate counting. Her HbA1c is 48 mmol/mol. Continuous glucose monitoring reveals multiple episodes of glucose <3.0 mmol/L, including nocturnal episodes. She has normal renal function and no evidence of gastroparesis. What is the most important factor contributing to her impaired hypoglycaemia awareness?
- A. The use of long-acting insulin analogue rather than intermediate-acting insulin
- B. Autonomic neuropathy resulting from long-standing diabetes
- C. Recurrent hypoglycaemia causing reduced counter-regulatory hormone responses (Correct Answer)
- D. Overly strict glycaemic control with HbA1c target that is too low
- E. Defective glucagon secretion specific to insulin degludec use
Explanation: ***Recurrent hypoglycaemia causing reduced counter-regulatory hormone responses***- Recurrent low glucose episodes lead to **hypoglycaemia-associated autonomic failure (HAAF)**, where the brain adapts by lowering the threshold for triggering a **sympathoadrenal response**.- This creates a vicious cycle where frequent lows diminish the **warning symptoms** and the hormonal counter-regulation (especially **epinephrine**) needed to raise blood sugar naturally.*The use of long-acting insulin analogue rather than intermediate-acting insulin*- **Long-acting insulin analogues** like degludec generally have a lower risk of nocturnal hypoglycaemia compared to **NPH (intermediate-acting) insulin** due to their flatter profiles.- Switching to an analogue is often an intervention to **reduce hypoglycaemia risk**, not the primary cause of impaired awareness.*Autonomic neuropathy resulting from long-standing diabetes*- While **autonomic neuropathy** can impair the heart rate response to low glucose, it is less commonly considered the primary cause of **impaired hypoglycaemia awareness** itself.- The patient's loss of **neuroglycopenic awareness** (warning symptoms) is primarily due to central nervous system adaptation, not directly peripheral nerve damage.*Overly strict glycaemic control with HbA1c target that is too low*- An **HbA1c of 48 mmol/mol** (6.5%) is a standard and often recommended target for many Type 1 diabetics and is not inherently considered **'too low'** in general guidelines.- While aggressive control *can* increase hypoglycaemia risk, this HbA1c alone doesn't suggest an overly strict target as the *most important* factor for *impaired awareness* in a patient with frequent documented lows.*Defective glucagon secretion specific to insulin degludec use*- **Defective glucagon secretion** is a common feature of long-standing Type 1 diabetes itself, regardless of the specific insulin used.- There is no evidence suggesting that **insulin degludec** specifically causes or exacerbates defective glucagon secretion compared to other insulins.
Question 69: A 72-year-old man with mechanical mitral valve replacement is established on warfarin with target INR 2.5-3.5. He is diagnosed with a new deep vein thrombosis and his current INR is 2.2. He has eGFR of 58 ml/min/1.73m² and weighs 82kg. What is the most appropriate management of his anticoagulation for the acute DVT?
- A. Switch from warfarin to apixaban 10mg twice daily for 7 days then 5mg twice daily
- B. Start low molecular weight heparin at treatment dose and increase warfarin dose targeting INR 3.0-4.0 (Correct Answer)
- C. Continue current warfarin dose and add low molecular weight heparin until INR >3.0 for 2 consecutive days
- D. Double the warfarin dose immediately and check INR daily until therapeutic
- E. Start intravenous unfractionated heparin and continue current warfarin dose
Explanation: ***Start low molecular weight heparin at treatment dose and increase warfarin dose targeting INR 3.0-4.0***- This patient experienced a new **deep vein thrombosis (DVT)** despite being on warfarin for a **mechanical mitral valve**, indicating that the current anticoagulation (INR 2.2, target 2.5-3.5) is insufficient.- For recurrent or breakthrough thrombosis on warfarin, especially with a **mechanical valve**, guidelines recommend **intensifying anticoagulation** by increasing the target **INR range (e.g., to 3.0-4.0)** and initiating **low molecular weight heparin (LMWH)** as a bridge until the new, higher target INR is achieved.*Switch from warfarin to apixaban 10mg twice daily for 7 days then 5mg twice daily*- **Direct Oral Anticoagulants (DOACs)** like apixaban are **contraindicated** in patients with **mechanical heart valves** due to an increased risk of stroke and valve thrombosis.- Clinical trials, such as the **RE-ALIGN trial**, have demonstrated significantly worse outcomes (increased thrombotic events and bleeding) when DOACs are used in this specific patient population.*Continue current warfarin dose and add low molecular weight heparin until INR >3.0 for 2 consecutive days*- Continuing the **current warfarin dose** is inappropriate because the patient developed a DVT, signifying **treatment failure** at the existing therapeutic level and target range.- The appropriate strategy for breakthrough thrombosis on warfarin is to **escalate the INR target** to a higher, more intense range, not simply to achieve a target within the previously failed range.*Double the warfarin dose immediately and check INR daily until therapeutic*- **Doubling the warfarin dose** immediately carries a high risk of significant **over-anticoagulation** and **bleeding** once the drug reaches a steady state, due to its variable patient response and delayed action.- This approach does not provide the **immediate anticoagulation** needed for an acute DVT; bridging with a rapid-acting anticoagulant like LMWH is crucial for acute management.*Start intravenous unfractionated heparin and continue current warfarin dose*- While **unfractionated heparin (UFH)** is an effective acute anticoagulant, **low molecular weight heparin (LMWH)** is generally preferred for DVT management in patients with stable renal function (eGFR 58 ml/min/1.73m²) due to its easier administration and predictable pharmacokinetics.- Similar to other incorrect options, continuing the **current warfarin dose** is inadequate as the patient's DVT indicates the need for a **higher INR target range** to prevent further thrombotic events.
Question 70: A 59-year-old man with type 2 diabetes is on basal-bolus insulin therapy (insulin glargine 36 units at bedtime and insulin aspart 12 units three times daily before meals). He reports recurrent hypoglycaemic episodes between 3-4 AM, with blood glucose readings of 2.8-3.2 mmol/L on multiple occasions. His bedtime glucose readings are typically 8-10 mmol/L and his pre-lunch and pre-dinner readings are well controlled at 5-7 mmol/L. What is the most appropriate modification to his insulin regimen?
- A. Switch from once-daily to twice-daily insulin glargine dosing
- B. Reduce his bedtime insulin glargine dose by 10-20% (Correct Answer)
- C. Reduce his evening mealtime insulin aspart dose by 2-4 units
- D. Increase his bedtime insulin glargine dose and advise a bedtime snack
- E. Add a bedtime dose of rapid-acting insulin
Explanation: ***Reduce his bedtime insulin glargine dose by 10-20%***- The patient is experiencing recurrent **nocturnal hypoglycaemia** (3-4 AM) with low blood glucose readings, which directly indicates that the **basal insulin** (insulin glargine) dose administered at bedtime is excessive.- A dose reduction of **10-20%** is the most appropriate and safest initial step to prevent further hypoglycaemic episodes without significantly compromising overall glycemic control, especially since other readings are well-managed.*Switch from once-daily to twice-daily insulin glargine dosing*- While **splitting basal insulin** can sometimes improve glycemic control by providing more even coverage, it does not directly address the underlying issue of an **absolute excess** of basal insulin causing nocturnal hypoglycemia.- The primary goal here is to reduce the total effective basal insulin overnight, which is best achieved through a **dose reduction** rather than a dosing schedule change that might still lead to excess.*Reduce his evening mealtime insulin aspart dose by 2-4 units*- **Insulin aspart** is a **rapid-acting insulin** with a duration of action of typically 2-5 hours; therefore, its effect would have largely worn off by 3-4 AM.- Reducing the evening mealtime dose would primarily impact **post-dinner glucose levels** and would not prevent the early morning nocturnal hypoglycemia caused by the long-acting glargine.*Increase his bedtime insulin glargine dose and advise a bedtime snack*- Increasing the **insulin glargine dose** would exacerbate the already problematic **nocturnal hypoglycaemia** and significantly heighten the risk of severe adverse events.- Advising a **bedtime snack** is a compensatory measure for excessive insulin and can lead to unwanted **weight gain** and suboptimal long-term glycemic management rather than fixing the insulin imbalance.*Add a bedtime dose of rapid-acting insulin*- Adding a **rapid-acting insulin** dose at bedtime when glucose levels are already 8-10 mmol/L would likely cause immediate and dangerous **hypoglycaemia** much earlier in the night (e.g., within 1-3 hours of injection).- Bedtime rapid-acting insulin is typically used for specific correction doses when blood glucose is significantly elevated, which is not the case for this patient's bedtime readings.
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