What is U-500 insulin ?
U-500 is regular insulin that is available in United States since the year 1952. However, recently doctors have started prescribing this medicine commonly to patients who require high doses of insulin in order to control their blood sugar level. This medicine is prescribed for patients who are facing increasing obesity along with type 2 diabetes and their bodies have become resistant to insulin. This resistance to insulin necessitates the need of insulin of more than 200 units/day.
At present, several health care professionals are unaware of this concentrated insulin formulation. U-500 has pharmacodynamic and pharmacokinetic profile which makes it different from U-100 human insulins as well as analogues. There is no specific clinical trial to prove the efficiency of U-500 insulin. However, there is an eight case series that has been published. It reports infrequent or rare occurrence of hypoglycaemia with use of U-500 insulin. The medication errors that are linked with the use of U-500 insulin are generally due to dispensing and administrating errors. The pharmacists that prescribe U-500 should be aware of complex issues associated with its correct prescribing and dispensing. Patients should be properly guided about its use to minimize the errors related to its administration and dosage.
U-500 Insulin – Insulin Pumps
Only very experienced medical practitioner should use U-500 insulin with insulin pumps. Lots of care is required for giving such concentrated insulin to patients. Generally U-500 pumps are given to those patients who require about 3 units/hr basal rate with U-100 insulin that causes inconvenient as well as frequent infusion set, battery changes and insulin cartridge. Due to lack of software required for U-500, programming is done in the pump units (20% of actual units of U-500) and the ratios of basal to bolus doses make the normal pump dosage. Single basal rate is generally selected at the starting and it is then adjusted with the values of blood glucose levels. Bolus dosing on the other hand is based on the count of carbohydrate or as per the scheduled meal plans.
U-500 Insulin Dosing
It may be intimidating to prescriber, patient or pharmacist to start therapy with U-500 insulin as it contains high doses of concentrated insulin. However, the patients requiring U-500 insulin are generally habitual of taking high doses of U-100 insulin and still have problem of hyperglycaemia. Starting U-500 regimen may solve their problem, if taken in appropriate way.
The dosing advice for U-500 is based on experience. The initial dose of U-500 can be calculated with the help of sum of TDD of U-100 insulin (basal and prandial or premix) after conforming from the actual home dosage of the patient.
Simplified Algorithm for Dosage Conversion to U-500 Insulin Therapy Based on a Patient’s Previous TDD of U-100 Insulin3,a
|
Required TDDb(Units) |
Route and Frequencyc,d |
U-500 Insulin Dosagee |
|
150–300 |
Twice daily | 50/50 or 60/40 before breakfast and supper |
| Three times daily | 33/33/33 before meals | |
| CSII | Three mealtime bolus doses = 50% TDD plus 24-hr basal insulin infusion = 50% TDD | |
|
300–600 |
Three times daily | 33/33/33 before meals |
| Four times daily | 30/30/30/10 (mealtimes and bedtime) | |
| CSII | Three mealtime bolus doses = 50% TDD plus 24-hr basal insulin infusion = 50% TDD | |
|
>600 |
Four times daily | 30/30/30/10 (mealtimes and bedtime) |
U-500 Insulin Syringes
Only tuberculin syringes can be used for administrating U-500 insulin, instead of normal insulin syringe. Great caution should be exercised while giving U-500 dosage to patients to avoid any case of over dosage.
References:
http://www.medscape.com/viewarticle/728505
http://www.medscape.com/viewarticle/728505_5
http://www.patientsafety.gov/alerts/AL09-15U-500InsulinAlert.pdf
by on 10. Oct, 2011 in diabetes treatment
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