Safe Prescribing — MCQs
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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?
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?
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?
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?
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?
Safe Prescribing UK Medical PG Practice Questions and MCQs
Question 1: 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?
- A. Amoxicillin 500mg TDS for 7 days
- B. Trimethoprim 200mg BD for 3 days (Correct Answer)
- C. Ciprofloxacin 500mg BD for 7 days
- D. Nitrofurantoin 50mg QDS for 3 days
- E. Co-amoxiclav 625mg TDS for 7 days
Explanation: ***Trimethoprim 200mg BD for 3 days***- This is a standard, highly effective **short course** regimen (3 days) recommended for community-acquired, uncomplicated **cystitis** in non-pregnant women, provided local **E. coli** resistance rates are acceptable (typically <20%).- Short courses improve adherence and minimize **collateral damage** (disruption of normal flora) and secondary resistance compared to longer courses.*Amoxicillin 500mg TDS for 7 days*- Amoxicillin monotherapy is unsuitable as first-line treatment for UTIs due to extremely high rates of **E. coli resistance** globally and poor efficacy in many regions.- The 7-day duration is unnecessarily long for uncomplicated **cystitis**, increasing antibiotic exposure and the risk of adverse effects.*Ciprofloxacin 500mg BD for 7 days*- **Fluoroquinolones** (like Ciprofloxacin) are generally reserved for complicated UTIs, **pyelonephritis**, or cases where first-line agents fail, due to resistance concerns and potential serious side effects.- A 7-day course is excessive. Uncomplicated cystitis usually requires only 3–5 days of effective therapy; 7 days is more appropriate for treating **pyelonephritis**.*Nitrofurantoin 50mg QDS for 3 days*- **Nitrofurantoin** is a preferred first-line agent, but the standard recommended regimen is typically 100mg BD for 5 days (or 50mg QDS for 5–7 days).- While highly effective against E. coli, a 3-day course of Nitrofurantoin is less established compared to the standard 3-day course used for **Trimethoprim** for uncomplicated cystitis.*Co-amoxiclav 625mg TDS for 7 days*- **Co-amoxiclav** (Amoxicillin/Clavulanate) is not a first-line agent for uncomplicated cystitis as it is a broad-spectrum antibiotic and increases the risk of **Clostridioides difficile infection** (CDI).- The 7-day duration is unnecessarily prolonged for treating simple **cystitis** in this patient, contributing to antibiotic selection pressure.
Question 2: 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?
- A. Continue insulin glargine at usual dose; omit insulin lispro while nil by mouth (Correct Answer)
- B. Continue insulin glargine; give insulin lispro based on blood glucose readings every 4 hours
- C. Stop all insulin until he is eating and drinking again
- D. Convert to variable-rate intravenous insulin infusion at 0.05 units/kg/hour
- E. Give half the usual total daily insulin dose as basal insulin only
Explanation: ***Continue insulin glargine at usual dose; omit insulin lispro while nil by mouth*** - Patients with **Type 1 diabetes** have an absolute insulin deficiency and require continuous **basal insulin** (glargine) to prevent the development of **diabetic ketoacidosis (DKA)**, even when not eating. - **Prandial insulin** (lispro) should be omitted while the patient is **nil by mouth** (NBM) to avoid hypoglycemia, as it is designed to cover carbohydrate intake. *Continue insulin glargine; give insulin lispro based on blood glucose readings every 4 hours* - While **glargine** must continue, scheduled **lispro** is for mealtime coverage; giving it every 4 hours without food intake significantly increases the risk of severe **hypoglycemia**. - High blood glucose readings in an NBM patient should be managed with specific **correction doses** or a variable-rate intravenous insulin infusion if clinically indicated, not routine prandial boluses. *Stop all insulin until he is eating and drinking again* - Stopping all insulin in a Type 1 diabetic is dangerous and will lead to **diabetic ketoacidosis (DKA)** within hours because basal insulin is essential to suppress hepatic glucose production and **ketogenesis**. - Total cessation of insulin is a common clinical error that must be avoided in **Type 1 diabetes** management during acute illness, regardless of nutritional status. *Convert to variable-rate intravenous insulin infusion at 0.05 units/kg/hour* - **Variable-rate intravenous insulin infusion (VRIII)** is typically reserved for metabolically unstable patients (e.g., DKA, severe hyperglycemia, major surgery, critical illness). - For a stable NBM patient with Type 1 diabetes, continuing their **usual subcutaneous basal insulin** is generally preferred as it is simpler and maintains a steady physiological insulin level. *Give half the usual total daily insulin dose as basal insulin only* - Arbitrarily reducing the **basal insulin dose** by half risks insufficient insulin coverage, potentially leading to **hyperglycemia** and metabolic decompensation, especially during acute stress. - The **standard dose of basal insulin** should generally be maintained in Type 1 diabetics to reflect their continuous physiological requirements and prevent DKA.
Question 3: 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?
- A. Continue apixaban 5mg twice daily throughout chemotherapy; monitor platelets weekly
- B. Reduce apixaban to 2.5mg twice daily during chemotherapy cycles
- C. Switch to prophylactic-dose LMWH during chemotherapy cycles
- D. Switch to warfarin with target INR 2-3 as it can be more easily reversed
- E. Temporarily stop all anticoagulation during chemotherapy cycles; restart when platelets >50 × 10⁹/L (Correct Answer)
Explanation: ***Temporarily stop all anticoagulation during chemotherapy cycles; restart when platelets >50 × 10⁹/L*** - For patients with **thrombocytopenia**, the bleeding risk from therapeutic anticoagulation significantly outweighs the stroke prevention benefit when the **platelet count drops below 50 × 10⁹/L**. - This strategy minimizes the risk of **life-threatening hemorrhage** during the anticipated chemotherapy-induced nadir while allowing for the resumption of protection once platelets recover. *Continue apixaban 5mg twice daily throughout chemotherapy; monitor platelets weekly* - Maintaining full-dose **DOAC therapy** with a platelet count between 20-50 × 10⁹/L carries an unacceptably high risk of **major bleeding**. - Weekly monitoring is insufficient to prevent acute bleeding events when severe **platelet suppression** is actively occurring due to cytotoxic agents. *Reduce apixaban to 2.5mg twice daily during chemotherapy cycles* - Dose reduction of **apixaban** is only indicated for specific criteria (age ≥80, weight ≤60kg, or creatinine ≥133 μmol/L); reducing it for **thrombocytopenia** is not evidence-based. - A reduced dose may still cause significant bleeding at low platelet levels while providing **sub-therapeutic stroke prevention**. *Switch to prophylactic-dose LMWH during chemotherapy cycles* - **Prophylactic-dose LMWH** is inadequate for stroke prevention in a patient with a high **CHA₂DS₂-VASc score** of 4. - In the setting of severe thrombocytopenia, even low-dose anticoagulation is often contraindicated until platelets reach a safer threshold. *Switch to warfarin with target INR 2-3 as it can be more easily reversed* - **Warfarin** is notoriously difficult to manage during chemotherapy due to **drug-nutrient interactions**, nausea, and fluctuating liver function. - The risk of **intracranial hemorrhage** is significantly higher with warfarin compared to DOACs, especially when **platelet counts** are unstable.
Question 4: 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?
- A. Split insulin detemir to twice-daily dosing (20 units morning, 20 units evening)
- B. Increase insulin detemir to 44 units at 22:00
- C. Add prandial rapid-acting insulin with main meals (Correct Answer)
- D. Switch from insulin detemir to insulin glargine
- E. Add a GLP-1 receptor agonist
Explanation: ***Add prandial rapid-acting insulin with main meals*** - The patient's **fasting glucose** is within target (6-8 mmol/L), indicating the current **basal insulin** dose effectively covers overnight hepatic glucose production. - The significant elevation in **pre-lunch** and **pre-dinner** readings demonstrates inadequate coverage of **post-prandial glucose excursions**, necessitating a **basal-bolus** regimen. *Split insulin detemir to twice-daily dosing (20 units morning, 20 units evening)* - Splitting the dose is typically used when **basal insulin** does not last 24 hours, leading to rising glucose before the next dose, which is not the case here given the stable **fasting readings**. - This adjustment would not provide the rapid peaks required to control **meal-related glucose spikes** seen in this patient. *Increase insulin detemir to 44 units at 22:00* - Increasing the **basal dose** when fasting levels are already at target (6-8 mmol/L) significantly increases the risk of **nocturnal hypoglycemia**. - Basal insulin is designed to manage background levels and is inefficient at controlling high **post-prandial hyperglycemia**. *Switch from insulin detemir to insulin glargine* - Both are **long-acting basal analogues**; switching between them primarily addresses duration of action or injection site reactions rather than **post-prandial control**. - Glargine would still provide a relatively **flat peakless profile**, failing to address the 12-15 mmol/L spikes seen during the day. *Add a GLP-1 receptor agonist* - While **GLP-1 receptor agonists** help with post-prandial glucose and weight, the clinical priority for a patient already on significant insulin with an **HbA1c of 8.4%** is often rapid titration via a **basal-bolus** insulin strategy. - In the context of "optimizing her **insulin regimen**," adding a rapid-acting bolus is the standard pharmacodynamic escalation to match mealtime carbohydrates.
Question 5: 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?
- A. Give 4-factor prothrombin complex concentrate 50 units/kg before surgery (Correct Answer)
- B. Proceed to surgery; accept increased bleeding risk as surgery is life-saving
- C. Give fresh frozen plasma 15 ml/kg before surgery
- D. Delay surgery 12 hours to allow rivaroxaban clearance
- E. Give tranexamic acid 1g IV before surgery
Explanation: ***Give 4-factor prothrombin complex concentrate 50 units/kg before surgery*** - For life-threatening emergency surgery in patients taking **Direct Oral Anticoagulants (DOACs)** like **rivaroxaban**, reversal is required to prevent catastrophic bleeding; **4-factor PCC** (50 units/kg) is recommended when specific antidotes like andexanet alfa are unavailable. - Given the patient's **eGFR of 58 ml/min** and that the last dose was only **8 hours ago**, significant anticoagulant activity remains as the half-life of rivaroxaban is approximately 5–9 hours. *Proceed to surgery; accept increased bleeding risk as surgery is life-saving* - Proceeding without reversal in a major abdominal surgery like a **laparotomy** carries an unacceptably high risk of **uncontrolled intraoperative hemorrhage**. - Standard of care mandates attempting to restore **hemostasis** before high-risk emergency procedures when the patient is fully anticoagulated. *Give fresh frozen plasma 15 ml/kg before surgery* - **Fresh frozen plasma (FFP)** is ineffective for reversing the effects of **Factor Xa inhibitors** because it lacks the concentration of clotting factors needed to overwhelm the drug effect. - Using FFP would require **large volumes** to provide even minimal pro-coagulant effect, risking fluid overload without providing adequate reversal. *Delay surgery 12 hours to allow rivaroxaban clearance* - **Perforated diverticulitis** is a surgical emergency where delay increases the risk of **fecal peritonitis**, severe **sepsis**, and mortality. - Anticoagulation should be reversed pharmacologically rather than waiting for **metabolic clearance** when the clinical situation is time-critical. *Give tranexamic acid 1g IV before surgery* - **Tranexamic acid** is an **antifibrinolytic** agent that prevents the breakdown of clots; it does not neutralize the **Factor Xa inhibition** caused by rivaroxaban. - While it may be used as an adjunct, it is not a sufficient primary management strategy for **reversing anticoagulant effects** in an emergency.
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