Treatment algorithm
Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer
Primary options
insulin glargine: injected subcutaneously once daily
or
insulin isophane human (NPH): injected subcutaneously twice daily
or
insulin detemir: injected subcutaneously twice daily
or
insulin degludec: injected subcutaneously once daily
-- AND --
insulin neutral: injected subcutaneously two to three times daily
or
insulin lispro: injected subcutaneously pre-meal
or
insulin aspart: injected subcutaneously pre-meal
or
insulin glulisine: injected subcutaneously pre-meal
OR
pump: uses regular insulin or insulins lispro, aspart, or glulisine
An initial total daily dose of insulin in adults can be 0.2 to 0.4 units/kg/day. In children an initial daily dose will be 0.5 to 1.0 units/kg/day, and during puberty the requirements may increase to as much as 1.5 units/kg/day. Often, when first started on insulin, patients with type 1 diabetes will experience a honeymoon period, during which they may require only 10 or 15 units/day. One half of the total dose is given as basal insulin and one half as bolus dosing. The bolus dosing is divided and given before meals. Patients need to self-monitor their blood glucose levels. The insulin doses can be adjusted every 2-3 days to maintain pre-meal and post-meal blood glucose targets.[1]
The simplest approach to covering mealtime insulin requirements is to suggest a range of doses, such as 4 units for a small meal, 6 units for a medium-sized meal, and 8 units for a larger meal. For greater flexibility of carbohydrate content of meals, pre-meal insulin can be calculated based on the estimated amount of carbohydrate in the meal and the patient's individual insulin-to-carbohydrate ratio. A simple beginning approach is to use one unit of mealtime insulin for every 15 g of carbohydrate in the meal. Patients can use the carbohydrate content per serving listed on food packaging to assess the number of grams in their anticipated meal, but carbohydrate counting is best learned with the help of a nutritionist. Using a food diary and 2-hour postprandial blood glucose measurements, the insulin-to-carbohydrate ratio can be adjusted.
Reasonable to begin therapy with 2-4 insulin injections daily to cover basal insulin requirements and to cover mealtime insulin needs. Intermediate- or long-acting insulins to cover basal, and short- or rapid-acting to cover mealtime needs, should be used.
Regular and NPH insulins are less expensive than the insulin analogues. Regular insulin is given about 30 minutes prior to the meal, while rapid-acting insulins (lispro, aspart, or glulisine) can be injected 15 minutes before to shortly after a meal. In children with erratic eating habits, rapid-acting insulins can be given just after the meal. NPH and insulin detemir are injected twice daily while insulin glargine can be injected once daily. The regimen should be individualised to obtain the best possible glycaemic control.
A correction dose may be incorporated into the insulin doses based on pre-meal glucose levels.
Patients with interest and good self-management skills may prefer to use an insulin pump.
Treatment recommended for SOME patients in selected patient group
A correction dose may be added to the bolus insulin based on the pre-meal blood glucose level. Correction dosing may be calculated as follows when the patient's total daily dose of insulin (TDD) and food intake is stable: 1800/TDD = the predicted point drop in blood glucose per unit of rapid acting insulin. For example, if the TDD is 40 units of insulin, 1800/40 = 45 point drop per unit of insulin.
Example of correction dosing based on pre-meal glucose and above calculation:
2.2 to 4.9 mmol/L (45-90 mg/dL): subtract 1 unit from mealtime insulin
5.0 to 7.4 mmol/L (91-135 mg/dL): add 0 units of correction insulin
7.5 to 9.9 mmol/L (136-180 mg/dL): add 1 unit of correction insulin
9.9 to 12.4 mmol/L (181-225 mg/dL): add 2 units of correction insulin
12.4 to 14.5 mmol/L (226-270 mg/dL): add 3 units of correction insulin
14.5 to 17.3 mmol/L (271-315 mg/dL): add 4 units of correction insulin
17.4 to 19.8 mmol/L (316-360 mg/dL): add 5 units of correction insulin
19.8 to 22.3 mmol/L (361-405 mg/dL): add 6 units of correction insulin
>22.3 mmol/L (>405 mg/dL): add 7 units of correction insulin; seek medical assistance.
The number used to calculate the correction dose may be as low as 1500 or as high as 2200. There are no specific guidelines to determine this number. In general, a lower number should be used for obese, insulin-resistant patients, and a higher number should be used for lean, insulin-sensitive patients.
This correction dose can be added to the patient's mealtime insulin requirement (whether based on general meal size or carbohydrate counting) and given as the total bolus dose.
Treatment recommended for SOME patients in selected patient group
Primary options
pramlintide: 15-60 micrograms subcutaneously before each meal
Synthetic analogue of human amylin, a protein that is co-secreted with insulin by pancreatic beta cells. It reduces postprandial glucose increases by prolonging gastric emptying time, reducing postprandial glucagon secretion, and reducing food intake through centrally mediated appetite suppression.[92]
May be given as an injection before each meal to get more stable glycaemic control. However, insulin treatment must continue in addition to pramlintide.
At initiation the current pre-meal insulin dose should be reduced by about 50% to avoid hypoglycaemia, and then titrated up.
Indicated as adjunctive treatment in patients with postprandial hyperglycaemia that cannot be controlled with pre-meal insulin alone. For example, it may be useful in a patient with high postprandial glucose, but who develops late hypoglycaemia when pre-meal insulin is increased.
Should not be used in a patient with gastroparesis. The most common side effect is nausea, occurring in 28% to 48% of patients.[92]
Primary options
insulin isophane human/insulin neutral: (50/50, 70/30) injected subcutaneously twice daily
OR
insulin aspart protamine/insulin aspart: (70/30) injected subcutaneously twice daily
OR
insulin lispro protamine/insulin lispro: (50/50, 75/25) injected subcutaneously twice daily
OR
insulin degludec/insulin aspart: (70/30) injected subcutaneously once or twice daily
Fixed-dose insulin is used when patients are already doing well on a fixed-dose regimen; or cannot manage 3-4 insulin injections daily; or have trouble mixing insulin.
Primary options
insulin isophane human (NPH): injected subcutaneously twice daily
or
insulin detemir: injected subcutaneously twice daily
-- AND --
insulin neutral: injected subcutaneously two to three times daily
or
insulin lispro: injected subcutaneously pre-meal
or
insulin aspart: injected subcutaneously pre-meal
Secondary options
insulin glargine: injected subcutaneously once daily
-- AND --
insulin neutral: injected subcutaneously two to three times daily
or
insulin lispro: injected subcutaneously pre-meal
or
insulin aspart: injected subcutaneously pre-meal
OR
pump: uses regular insulin or insulins lispro or aspart
Blood sugar goals, if able to be achieved without significant hypoglycaemia, are fasting <5 mmol/L (<90 mg/dL), 1-hour postprandial <7.2 to 7.8 mmol/L (<130-140 mg/dL), and 2-hour postprandial <6.7 mmol/L (<120 mg/dL). If these targets result in hypoglycaemia, less stringent targets are appropriate.[1]
HbA1c should be <48 mmol/mol (<6.5%) before conception, if it can be achieved without hypoglycaemia.[1] HbA1c in pregnancy can be monitored monthly.[1]
Patients should monitor their blood glucose from 4-7 times per day and the pattern should be examined every few weeks early in pregnancy so that nutrition content and timing, exercise patterns, and the insulin doses can be modified to achieve optimal control.
Insulin requirements generally increase early in pregnancy, then decrease from about 8-16 weeks before rising throughout the rest of the pregnancy.
Commonly used insulins during pregnancy include NPH, detemir, regular, lispro, and aspart.[88] Use of CGM during pregnancy may help in improving glycaemic control and neonatal outcomes.[89] There are no large randomised trials supporting the safety of insulin glargine in pregnant patients with diabetes. However, insulin glargine has been safely used in many patients during pregnancy. It can be considered second-line to NPH or insulin detemir for basal insulin dosing during pregnancy because there are fewer long-term safety monitoring data. There are few data comparing outcomes for continuous subcutaneous insulin infusion versus multiple daily injections of insulin for pregnant women with diabetes.[90]
Treatment recommended for ALL patients in selected patient group
Primary options
aspirin: 75-150 mg orally once daily, usual dose 75 mg/day
The American Diabetes Association recommends that all pregnant women with pre-existing type 1 diabetes should consider daily low-dose aspirin starting at the end of the first trimester in order to reduce the risk of pre-eclampsia.[1]
Use of this content is subject to our disclaimer