Insulin

1. Insulin Refresher slides Date of preparation: June 2017 Review date: June 2018 Prepared by Donna Chorley, Pharmacist

2. Insulin refresher session • Types of insulin • Insulin regimens • Insulin errors • Intravenous insulin • Variable Rate Intravenous Insulin Infusion (VRIII) • Perioperative insulin use

3. INSULIN TYPES

4. Types of insulin • Rapid acting analogue • Short acting (human) • Intermediate acting (human) • Long acting analogue • Biphasic mixtures (human; analogue) • Porcine and bovine rarely used

5. INSULIN PROFILES

6. Rapid acting analogues NovoRapid (aspart) Humalog (lispro) Apidra (glulisine) ↓ risk of hypoglycaemia Short acting insulin Soluble insulin Actrapid; Humulin S; Insuman Rapid Slower onset Longer duration

7. Intermediate – Isophane Insulatard; Humulin I; Insuman Basal Provides background (basal) insulin (Type 2 patients) Long-acting analogues Levemir (detemir) Lantus (glargine) Tresiba (degludec) (42 hrs) Basal insulin (Type 1 & some Type 2)

8. Biphasic Human Humulin M3 Insuman Comb 15 Insuman Comb 25 Insuman Comb 50 Biphasic analogues NovoMix 30 Humalog Mix25 Humalog Mix50

9. Insulin regimens

10. Insulin Regimens • There is no single regimen that will suit all people • Lifestyle and eating habits need to be taken into consideration when deciding which regimen to use • Aim is to provide sufficient background (BASAL) insulin with BOLUS insulin to cover meals

11. Normal insulin secretion Short-lived, rapidly generated meal-related insulin peaks 70 60 50 40 Insulin (µU/ml) Low, steady, basal insulin profile 30 20 10 0 6:00 10:00 14:00 18:00 22:00 2:00 6:00 Time of day Polonsky KS et al. J Clin Invest 1988;81:442–8

12. Insulin regimens

13. Basal Bolus regimen • Allows greater flexibility • Uses rapid acting insulin just before each meal • Long acting insulin (Analogues can be given at any time but must be given same time every day) • Patients can adjust their dose according to CBG level, exercise and quantity of CHO to be eaten

14. Twice Daily regimen • Most common regimen used in UK • Biphasic insulin • Suitable for those with regular meal times and diet • Shorter acting component • Controls rise in glycaemic level after breakfast and evening meal • Longer acting component • Maintains glycaemic control from lunch until the early part of the evening and from late evening until the next morning • Snacks may be needed between meals and before bed to prevent hypoglycaemia

15. Once Daily Insulin • Type 2 only • Use of intermediate or long acting insulin • Insulatard, Humulin I • Lantus or Levemir (NICE criteria) • Needs to be given same time daily • Can be used in combination with oral antidiabetic medicines (SFU, gliptins) • Adjusted depending on pre breakfast blood glucose level

16. INSULIN ERRORS

17. Potential errors • Omission • Insulin name / insulin type • Administration time • Insulin dose • Transfer of information • Transcription • Discharge (to GP, to community nurse) • Use of “u” or “iu” instead of units • Wrong syringe

18. Avoiding omission • Know who is on insulin • Always prescribe on main prescription chart as: • “Insulin – see diabetic chart” • Endorse supplementary chart section • Plan ahead: • Ensure breakfast dose for next day prescribed • If patient stable prescribe weekend doses in advance • Ensure sufficient insulin in pen/vial for next 2 doses • If insulin due after a hypo • Treat hypo • Give insulin after dose review (with meal)

19. Insulin Names • Use brand names • Always write name in full • Humalog Mix 25 • Humulin I • NovoMix 30 • Common errors • Humalog instead of Humalog Mix 25 • Humulin instead of Humulin I or Humulin M3 • NovoRapid instead of NovoMix 30 • Lantus / Levemir confused

21. Doses • Variable • Type 1 patients generally lower doses • Type 2 patients generally higher doses • Idea from King’s College Hospital • Rapid / short acting or biphasic insulin • Confirm all doses over 25 units • Intermediate / long-acting insulins • Confirm all doses over 50 units • If patients carbohydrate counting • Prescribe meal insulin as dose range e.g. 2 to 6 units • Record number of units taken

22. Units • Never abbreviate units • The use of “u” and “i.u” can be misread - 10 fold increase in dose given • SGUH chart pre-printed “units” • Remember to write units in full for stat doses and for dose records • Leave a space between dose and units • 22 units not 22units

24. Administration times • Rapid acting / (short acting) • Always for meals • Intermediate – isophane • Once or twice daily • Usually bedtime if once daily • May be given in morning • Long-acting analogues • Once or twice daily • Anytime but must be same time everyday • Biphasic mixtures • Always for meals

26. Insulin Syringe • Insulin syringes must be used to measure and administer insulin doses unless a pen device is used • Non-insulin syringes never used • If staff administering insulin must use safety insulin syringes

27. Insulin Pens and Cartridges • One pen – one patient • Store in patient’s POD locker • Stable at room temperature for 4 weeks • Discard all insulin 4 weeks after opening • Do not withdraw insulin from a pen or cartridge with a syringe • If staff administering insulin must use safety needles (Patients who self-administer should use standard insulin pen needles)

28. Insulin Strength • All formulary insulins at SGUH 100 units in 1ml • Be aware of higher strength insulins • Tresiba 200 units in 1ml (Flextouch pen) • Humalog 200 units in 1ml (Kwikpen) • Toujeo 300 units in 1ml (Solostar pen)

29. Biosimilar insulins • Not currently stocked at SGUH • Abasaglar (insulin glargine 100 units in 1ml) • Toujeo (insulin glargine 300 units in 1ml) • Be aware not directly interchangeable with Lantus insulin • Seek advice if patient admitted without own supply • Dose reduction needed for switch to Lantus

30. Planning for discharge • Is patient new on insulin? • Can they self administer? • Refer to Diabetes Specialist Nurse before discharge – at least 48 hours notice • Is a nurse needed to administer / monitor? • Notify community team ≥ 48 hours before discharge • Ensure insulin name, dose and times due are clear • TTO documentation • Insulin name and device • Dose at discharge and whether changed • Use duration box if necessary • Request sufficient pens for 2 weeks if supply needed

31. INSULIN MONITORING

32. Glucose monitoring • Capillary blood glucose (CBG) • Lab sample if CBG “Hi” • How frequently? • Any specific situation? • Target range for inpatients: • 5 – 7 mmol/L (pre-meal) • Higher levels preferred for frail, older patients

33. Ketone monitoring • Important for patients with type 1 diabetes • Monitor for ketones • During periods of acute illness • eg infection, stress, GI disturbances • When CBG > 14 mmol/litre • During pregnancy • Presence of ketones indicates: • Need for therapy change • Possible impending / established ketoacidosis

34. Adjusting insulin doses • Basal bolus: • Adjust basal insulin to correct fasting glucose • Adjust bolus insulin dose for previous meal e.g. adjust breakfast insulin if pre-lunch BG high/low • Twice daily biphasic: • The breakfast injection affects the lunchtime and evening meal blood glucose • The evening injection affects the bed time level and the fasting level the next day

35. Insulin Titration • Adjust after several readings – review the trends • Every action has a consequence – make one adjustment at a time • Eliminate all hypoglycaemic episodes first • If need to reduce insulin dose – 10 to 20% reduction • Start the day with good glucose levels – if CBG high throughout day normalise fasting level first • If need to increase insulin dose - 10% increment • DON’T prescribe prn insulin

36. Insulin titration cont’d • PRIOR to adjusting DON’T forget to check: • Injections Sites – where is the insulin being injected? • What is the patient eating or drinking? • Has any new medication been initiated that could have affected the glucose levels? • Has the right insulin been prescribed?

37. Prescription review • Review the type of insulins patient is taking • Why is patient on basal insulin and a biphasic? • Why is the patient taking biphasic insulin and gliclazide? • Are the administration times correct? • Rapid/short and biphasic never given at bedtime

38. Intravenous insulin

39. Intravenous insulin – Indications • NBM (variable rate) • Peri-operative / Peri-procedure (variable rate) • DKA / HHS (fixed rate) • Patients who are vomiting (variable rate) • Patients with hyperglycaemia complicating acute renal, cardiac or liver failure (variable rate) • Treatment of hyperkalaemia (fixed rate)

40. Variable Rate Intravenous Insulin Infusion VRIII

41. Risks / Benefits • Advantages of VRIII • Flexibility for independent adjustment of fluid and insulin • Accurate delivery of insulin via syringe driver • Allows tight BG control in the intra-operative starvation period • Disadvantages of VRIII • Risk of adverse events leading to serious incidents • Reactive to BG levels not proactive • Increased staff time for monitoring • Delays and difficulties in transfer back to normal regimen may prolong length of stay

42. Insulin infusion rate • Rate determined by: • Insulin sensitivity • Type 1 patient on low dose subcutaneous insulin dose is sensitive to insulin and requires lower rate • Type 2 patient on large subcutaneous insulin doses is insulin resistant and requires higher rate • Whether long-acting insulin given in previous 12 hours • If Lantus or Levemir given basal requirements met and can infuse at lower rate with a zero option • If no basal insulin given need continuous infusion

43. Oral anti-diabetic agents but no s/c insulin – initial scale 1 or 2

45. Fluid management with iv insulin • Provide glucose as substrate (fuel) to prevent proteolysis, lipolysis and ketogenesis • Optimise intravascular volume status • Maintain serum electrolytes within normal ranges • Current recommendations • 0.45% NaCl + 5% glucose + 0.15% KCl • 0.45% NaCl + 5% glucose + 0.3% KCl

46. Monitoring • Capillary Blood Glucose (CBG) • Every hour • If out of range increase frequency • Potassium • Ideally every 4 hours (VRIII) • In practice if in range 2 readings in 24 hours acceptable • Sodium • Ideally every 4 hours (VRIII) • Cannula and infusion devices • Duration • Refer to diabetes team if duration > 24 hours

47. Monitoring blood glucose • Monitor CBG every hour • Aim for CBG range 6 to 10 mmol/L • If hyperglycaemia • CBG >12 mmol/L for 3 readings and not falling by ≥ 3mmol/L per hour • Ensure infusion devices and cannula patent • Prescriber to increase to next scale • If hypoglycaemia (CBG < 4mmol/L) • Reduce rate to 0.5 units/hour • If scale zero stop infusion until hypoglycaemia treated • Treat hypoglycaemia • Adjust scale once CBG > 4mmol/L

48. Successful IV Insulin Infusion Mmol/l 10 6 Desired Pattern Desired Pattern Undesirable Pattern

49. Hypoglycaemia • Most common side effect of iv insulin • Prevent by frequent CBG monitoring • Treat for “hypo avoidance” • Adjust insulin dose • 100 ml 10% glucose iv prn prescription

50. Stopping iv insulin • Patient eating and drinking; not vomiting • Intravenous insulin • Half life 3 to 5 minutes • Duration 20 to 30 minutes • First dose of subcutaneous insulin must be given 60 minutes before stopping iv • If basal insulin (Levemir, Lantus, Tresiba) continued alongside VRIII can stop VRIII at any time