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

Insulin safety - Free UK Medical PG Review

Quick Overview

Insulin prescribing errors cause significant morbidity and mortality, with ten-fold dosing errors being the most dangerous. Safe insulin prescribing requires clarity in documentation, understanding insulin types and their pharmacokinetics, and robust protocols for hypoglycemia prevention. NICE NG17 emphasizes avoiding abbreviations, precise dose calculations, and comprehensive patient education to minimize harm.

Core Facts & Concepts

📊 Insulin Types & Pharmacokinetics

Type	Onset	Peak	Duration	Examples
Rapid-acting	5-15 min	1-2 hrs	3-5 hrs	Aspart, Lispro, Glulisine
Short-acting	30-60 min	2-4 hrs	6-8 hrs	Human soluble (Actrapid)
Intermediate	1-2 hrs	4-12 hrs	16-24 hrs	Isophane (NPH)
Long-acting	1-2 hrs	Minimal	18-24 hrs	Glargine, Detemir, Degludec

💊 Safe Prescribing Rules (NICE NG17)

NEVER abbreviate "units" - write in full (prevents 10-fold errors: "6U" misread as "60")
Always write "units" after the number: "8 units" not "units 8"
Use BOTH generic and brand names for insulin (different devices/concentrations)
Prescribe insulin by brand name to avoid confusion between formulations
Standard concentration: 100 units/mL (U100) - always verify concentration
Specify device type: pen, cartridge, or vial with syringe

![Insulin pen showing dose dial with units clearly marked](Image: insulin pen dose dial)

🎯 Critical Dose Calculations

Total daily dose (TDD) = weight (kg) × 0.5-1 units/kg
Basal insulin = 40-50% of TDD (given once/twice daily)
Bolus insulin = 50-60% of TDD (divided across meals)
Correction dose = (current glucose - target glucose) ÷ insulin sensitivity factor

Problem-Solving Approach

Step-by-Step Safe Prescribing Protocol

Verify patient identity and current insulin regimen (check patient's own devices)
Calculate dose - double-check calculations independently
Write prescription clearly:
- Brand name + generic name
- Dose in units (never "U")
- Device type specified
- Timing relative to meals
Check for interactions - steroids, beta-blockers alter insulin requirements
Educate on hypoglycemia recognition: tremor, sweating, confusion, glucose <4 mmol/L
Provide sick day rules (see below)

Figure 1: Blood glucose meter displaying reading of 3.2 mmol/L indicating hypoglycemia

🚩 Red Flags for Insulin Safety

Dose >1.5 units/kg/day (risk of error or insulin resistance)
Rapid dose escalation without monitoring
Prescribing during acute illness without adjustment
Patient confusion about device/technique
Recurrent unexplained hypoglycemia (<4 mmol/L)

⚠️ Warning: Ten-fold errors occur when "U" is misread as "0" (e.g., "6U" → "60 units"). Always write "units" in full.

Analysis Framework

Sick Day Rules (Prevent DKA/Hypoglycemia)

Situation	Insulin Adjustment	Monitoring
Eating normally	Continue usual doses	Test glucose 4-hourly
Reduced oral intake	Continue basal; reduce bolus by 20-50%	Test 2-hourly; check ketones
Vomiting/unable to eat	Continue basal; omit bolus	Test hourly; seek help if ketones >1.5 mmol/L
Hyperglycemia (>15 mmol/L)	Give 10% correction dose every 2-4 hrs	Check ketones; admit if >3 mmol/L

Hypoglycemia Management Protocol

Conscious patient (<4 mmol/L): 15-20g fast-acting carbs (glucose tablets, 200mL juice)
Recheck at 15 minutes - repeat if still <4 mmol/L
Follow with long-acting carb (sandwich, biscuits) to prevent recurrence
Unconscious/unable to swallow: 1mg glucagon IM or 75-100mL 20% glucose IV

Visual Aid

Key Discriminators: Insulin Errors vs. Safe Practice

Error-Prone Practice	Safe Alternative
Writing "6U insulin"	Writing "6 units insulin"
"Insulin" without brand	"Lantus (insulin glargine)"
Verbal orders	Written prescription only
Dose without device	"10 units via KwikPen"

Key Points Summary

✓ Never abbreviate "units" - ten-fold errors are fatal; always write in full

✓ Prescribe by brand name with device type to prevent formulation confusion

✓ Standard concentration is 100 units/mL - always verify before administering

✓ Hypoglycemia threshold: <4 mmol/L - treat with 15-20g fast-acting carbs, recheck in 15 minutes

✓ Sick day rules: continue basal insulin always; reduce/omit bolus based on oral intake

✓ Basal insulin = 40-50% TDD; bolus = 50-60% TDD (starting dose 0.5-1 units/kg/day)

✓ Red flag: recurrent unexplained hypos - review technique, timing, and dose calculations

📌 Remember: INSULIN - Independent check, Never abbreviate units, Specify brand, Understand pharmacokinetics, Label device, Instruct on hypos, No verbal orders

Insulin safety

Insulin safety

On this page

Quick Overview

Core Facts & Concepts

Problem-Solving Approach

Analysis Framework

Visual Aid

Key Points Summary

Practice Questions: Insulin safety

Flashcards: Insulin safety

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