- There is a significant difference in blood flow to various anatomic sites of injection (abdomen, deltoid, gluteus, and thigh) responsible for variability in insulin absorption and effect. Patients should therefore avoid random use of different body regions for their injections. For example, if a patient prefers to use their thigh for a morning injection, this site should be used consistently for this injection.
- Patients on intermediate insulin (NPH) or premixed insulins should resuspend the product before use by rolling gently on their hands so as to improve absorption and reduce variation in bioavailability and effect.
- The elimination of injected insulin is primarily renal. Thus, patients with renal function impairment experience increased risk of hypoglycemic episodes. Insulin dosage should therefore be reduced in such patients.
- Timing of insulin injection is critical in blood sugar control. The timing is determined by the onset of action; regular insulin with a delayed onset of action of 30-60 minutes should be injected about 30 minutes before a meal whereas rapid-acting insulin analogs are injected 15-20 minutes pre-meal.
- Exposure to extremes of temperature can lead to loss of insulin effectiveness. Unopened insulin (i.e., not previously used) should be stored in the refrigerator at 2°C-8°C and never be frozen or kept in direct sunlight. However, Insulin vials , cartridges or pens may be kept at room temperature (15°C-30°C) for about 1 month.
- Regular insulin, the basal insulin analogs (glargine and detemir) and the rapid-acting insulin analogs (lispro, aspart and glulisine) are clear and colorless, and should not be used if they become cloudy or viscous.
- To avoid the lipohypertrophic effects of insulin, patients should be instructed to rotate their insulin injection sites, preferably rotating within one area and not reusing for one week.
- When a dose of intermediate or long-acting insulin is adjusted, it is recommended to wait at least 2-5 days before further changes in the dose to assess the response.
In patients on set dose of pre-meal bolus insulin, post meal glucose variability can be controlled by having patients keep the carbohydrate content of the meal similar at mealtimes from day to day; Education in medical nutrition therapy is important.
- Exercise improves insulin sensitivity. Thus, when a patient exercises, it is often necessary to decrease the insulin dose (and/or increase caloric intake) to prevent hypoglycemia. And because the effect of exercise on insulin sensitivity can last for many hours, more than 1 insulin dose may need to be adjusted.
- Patients who are ill should be advised to continue their insulin therapy, maintain fluid intake, eat smaller meals as tolerated, and test their glucose levels every 1-4 hours (ketones as well for people with type 1 diabetes when glucose levels are over 200 mg/dl).
- Some insulin formulations are available at concentration higher than 100 units/ml (U-100) e.g. U-500, U-300. Since syringes for such concentrations are not available, extreme caution must be taken as each marked unit on a U-100 syringe will deliver larger units of insulin than anticipated. To avoid errors in insulin dosing, it is recommended that the dose for such preparations be written both as the number of units and the number of ml to be drawn.