Starting insulin treatment for adults with type 1 diabetes

Ideally, insulin treatment for adults with type 1 diabetes should be started by a multidisciplinary diabetes team.

Patients who have diabetic ketoacidosis (DKA) at first presentation require immediate hospital admission (see Diabetic ketoacidosis). Urgent referral to hospital is also required for patients presenting with severe hyperglycaemia; indicators for urgent referral are listed in Indicators for urgent referral of adults presenting with hyperglycaemia.

Insulin treatment comprises:

basal insulin—mandatory background insulin given over 24 hours, independent of carbohydrate intake; typically 40% of the total daily insulin dose (sum of all doses of insulin given daily, irrespective of formulation). It is usually long-acting insulin given once or twice daily. Twice-daily intermediate-acting insulin may occasionally be used
bolus insulin, comprising:
- prandial insulin—insulin given before meals to cover carbohydrate intake; usually rapid- or short-acting insulin
- supplemental (correction) doses of insulin—doses to reduce high blood glucose concentrations to target levels; usually rapid- or short-acting insulin given with the prandial bolus insulin dose to cover a meal, or given as a separate dose between meals.

For insulin formulations, see Action profiles of insulin formulations.

The usual insulin regimen for treating patients with type 1 diabetes is a multiple daily injection (basal–bolus) insulin regimen or a continuous subcutaneous insulin infusion. Mixed insulin regimens have a minimal role in managing adults with type 1 diabetes.

Thorough patient education and support is required for all patients with type 1 diabetes, especially in the early stages of insulin treatment. Self-administration of insulin is preferred, but may not always be possible; see Specific considerations when insulin is not self-administered.

Table 1. Action profiles of insulin formulations
Insulin formulations [NB1]: basal long-acting intermediate-acting bolus rapid-acting short-acting fixed-dose combination (biphasic premixed or coformulation) rapid-acting plus intermediate-acting short-acting plus intermediate-acting long-acting plus rapid-acting
basal: long-acting insulin [NB2]
brand names (presentations) [NB3] [NB4]	generic name	onset	peak	duration
Levemir (penfill, prefilled pen)	detemir 100 units/mL insulin, detemir insulin, detemir insulin, detemir	90 minutes	no peak	16 to 24 hours
Optisulin (cartridge, prefilled pen)	glargine 100 units/mL [NB5] insulin, glargine insulin, glargine insulin, glargine	1 to 2 hours	no peak	up to 24 hours
Toujeo (prefilled pen)	glargine 300 units/mL [NB5] insulin, glargine insulin, glargine insulin, glargine	1 to 6 hours	no peak	24 to 36 hours
basal: intermediate-acting insulin [NB6]
brand names (presentations) [NB3] [NB4]	generic name	onset	peak	duration
Humulin NPH (cartridge, vial) Protaphane (penfill, prefilled device, vial)	isophane (protamine suspension) 100 units/mL insulin, isophane + protamine sulfate insulin, isophane+protamine sulfate insulin, isophane+protamine sulfate	1 to 3 hours	5 to 8 hours	up to 18 hours
bolus: rapid-acting insulin [NB7]
brand names (presentations) [NB3] [NB4]	generic name	onset	peak	duration
Apidra (cartridge, prefilled pen, vial)	glulisine 100 units/mL insulin, glulisine insulin, glulisine insulin, glulisine	10 to 15 minutes	60 to 90 minutes	3 to 5 hours
Fiasp (prefilled pen, vial)	faster-acting aspart 100 units/mL [NB8] insulin, aspart insulin, aspart (including faster-acting aspart) insulin, aspart (including faster-acting aspart)	4 to 15 minutes	30 to 90 minutes	3 to 5 hours
Humalog (cartridge, prefilled pen, vial)	lispro 100 units/mL insulin, lispro insulin, lispro insulin, lispro	10 to 15 minutes	1 to 2 hours	3.5 to 4.75 hours
Humalog U200 (prefilled pen)	lispro 200 units/mL insulin, lispro insulin, lispro insulin, lispro	10 to 15 minutes	1 to 2 hours	3.5 to 4.75 hours
NovoRapid (penfill, prefilled pen, vial)	aspart 100 units/mL insulin, aspart insulin, aspart (including faster-acting aspart) insulin, aspart (including faster-acting aspart)	10 to 15 minutes	60 to 90 minutes	3 to 5 hours
bolus: short-acting insulin
brand names (presentations) [NB3] [NB4]	generic name	onset	peak	duration
Actrapid (penfill, vial) Humulin R (cartridge, vial) [NB9]	neutral 100 units/mL insulin, neutral insulin, neutral insulin, neutral	30 minutes	2 to 3 hours	6.5 hours
fixed-dose combination (biphasic premixed): rapid-acting plus intermediate-acting insulin
brand names (presentations) [NB3] [NB4]	generic name	notes
Humalog Mix25 (cartridge, prefilled pen) Humalog Mix50 (cartridge, prefilled pen)	lispro / lispro protamine 100 units/mL [NB10] insulin, lispro + protamine sulfate insulin, lispro+protamine sulfate insulin, lispro+protamine sulfate	fixed ratio of rapid-acting (bolus) insulin to intermediate-acting (basal) insulin in the brand name, the number refers to the % of bolus insulin
NovoMix30 (penfill, prefilled pen)	aspart / aspart protamine 100 units/mL [NB10] insulin, aspart + protamine sulfate insulin, aspart+protamine sulfate insulin, aspart+protamine sulfate
fixed-dose combination (biphasic premixed): short-acting plus intermediate-acting insulin
brand names (presentations) [NB3] [NB4]	generic name	notes
Humulin 30/70 (cartridge, vial) Mixtard 30/70 (penfill, prefilled device)	neutral / isophane 100 units/mL insulin, neutral + insulin, isophane insulin, neutral+insulin, isophane insulin, neutral+insulin, isophane	fixed ratio of short-acting (bolus) insulin to intermediate-acting (basal) insulin in the brand name, the first number refers to the % of bolus insulin, and the second number refers to the % of basal insulin
Mixtard 50/50 (penfill)	neutral / isophane 100 units/mL insulin, neutral + insulin, isophane insulin, neutral+insulin, isophane insulin, neutral+insulin, isophane
fixed-dose combination (biphasic coformulation): long-acting plus rapid-acting insulin
brand names (presentations) [NB3] [NB4]	generic name	notes
Ryzodeg 70/30 (penfill, prefilled pen)	degludec / aspart 100 units/mL [NB11] insulin, degludec / insulin, aspart insulin, degludec / insulin, aspart insulin, degludec / insulin, aspart	fixed ratio of long-acting (basal) insulin to rapid-acting (bolus) insulin in the brand name, in contrast to the fixed-dose combination insulins above, the first number refers to the % of basal insulin and the second number refers to the % of bolus insulin
Note: NB1: Not all insulin formulations are available on the Pharmaceutical Benefits Scheme (PBS); see the PBS website for current information. NB2: Long-acting insulin is generally given once daily but is sometimes required twice daily. NB3: At the time of writing, this contains a complete list of brands of insulin available in Australia. It is recommended to prescribe insulin by the brand name, to reduce the risk of error. If there are multiple brands of the same active ingredient, the same brand should be prescribed, dispensed and administered. Patient familiarity with one brand is important because instructions for use vary between brands. For more information, see the Australian Commission on Safety and Quality in Health Care’s List of medicines for brand consideration. NB4: Presentations of insulin available are cartridges or penfills (for use with reusable injector pens, continuous subcutaneous insulin infusion [CSII] pumps or insulin syringes), prefilled pens or devices (preloaded disposable injector pens or devices) and 10 mL vials (for use with CSII pumps or insulin syringes). NB5: Insulin glargine 300 units/mL (Toujeo) and insulin glargine 100 units/mL (Optisulin) are not directly interchangeable because they have different action profiles and are not bioequivalent. Dose adjustments are required when changing between the two concentrations. NB6: Intermediate-acting insulin is generally given twice daily. NB7: For ‘rapid-acting insulins’ listed in this table, the terminology used in other resources is variable. Some other resources use the term ‘ultra-short acting’ to describe rapid-acting insulins. Faster-acting insulin aspart (Fiasp) is sometimes described as an ‘ultra-rapid acting’ or ‘ultra-fast acting’ insulin. NB8: Faster-acting insulin aspart (Fiasp) includes the excipient nicotinamide, which increases the rate of insulin absorption. In clinical trials comparing faster-acting insulin aspart (Fiasp) to insulin aspart (Novorapid), the onset of action was 5 minutes faster and the time to maximum glucose infusion rate was 11 minutes earlier for faster-acting insulin aspart (Fiasp); however, the clinical significance of this is unclear. NB9: A high-concentration formulation of neutral insulin 500 units/mL (Humulin R U-500) may be used for patients requiring very high doses of insulin. It is not registered for use in Australia but is available via the Special Access Scheme. NB10: Aspart protamine (component of Novomix 30) and lispro protamine (component of Humalog Mix25 and Humalog Mix50) have similar action profiles to isophane (protamine suspension) (Humulin NPH, Protaphane). NB11: Degludec is a long-acting (basal) insulin with a duration of action of up to 42 hours. Some other resources describe degludec as an ‘ultra-long acting’ insulin. The degludec / aspart coformulation (Ryzodeg 70/30) is given up to 15 minutes before a meal, generally once daily before the largest carbohydrate-containing meal. It can also be given twice daily, divided between the 2 largest carbohydrate-containing meals.