Why Humulin R U500 insulin is prescribed - instructions for initiation
Your doctor has suggested that you should switch to a higher concentration of insulin. The regular concentration of insulin is 100 units per ml. The higher concentration insulin is 500 units per ml (Humulin R U500), and is used in patients requiring higher doses of insulin. Therefore, it is really important that you are aware that Humulin R U500 insulin is five times the strength of regular insulin.
Administering the insulin
Humulin R U500 insulin is now available in a calibrated pre-filled pen device called a Kwikpen®. This means you can dial up your insulin dose just like any other insulin pen by twisting the top of the device; the measuring system in the pen is pre-adjusted to account for the increased concentration of insulin. No calculations are needed. The pen is accessed with a normal pen needle such as BD Micro-Fine +. The Humulin R U500 Kwikpen only measures insulin in multiples of five units.
This will be explained and demonstrated clearly by the diabetes specialist team at the time of initiation of the insulin. The insulin is given subcutaneously (into tissue just beneath the skin), as with regular insulin. It must not be given intravenously due to risk of overdose.
Due to the high concentration of Humulin R U500 insulin, it can result in delayed absorption times. Each dose is generally active for eight hours, although it can last for 24 hours. The onset of action is usually around 30 minutes, peaking around one to three hours later. It is usually prescribed in two to three daily meal time injections. Due to the duration of insulin activity, background (long acting) insulin is not usually required.
When switching from regular insulin to Humulin R U500 insulin your total daily dose may be reduced by 20%. You will be advised of the new doses during the consultation. Doses must not be adjusted without the advice of your diabetes team.
Injection technique and sites remain the same. Rotation of sites remains very important in order to avoid ‘lumpy’ sites.
The contents of the pen should be visually inspected prior to each administration. Do not use if it has become viscous/thickened, cloudy or discoloured.
Monitoring the effect of the insulin
Regular blood glucose testing is required, before each meal and before bed, to observe for improvements or deterioration in diabetes control so doses can be adjusted accordingly. Management of hypoglycaemia remains the same. If you are unsure, liaise with the hospital diabetes specialist team.
Storage of insulin
Storage of Humulin R U500 Kwikpen is the same as regular insulin: i.e: when opened and in use, the pen may be stored outside of a fridge.
For unopened Humulin R U500 Kwikpens, these should be stored in a fridge. Once out of the fridge it should be discarded after 28 days, or the expiry manufacturer’s expiry on the device, whichever is sooner, so make a note of the date it is taken out of the fridge. Never store in the freezer.
Advice on hospital admission
During an admission to hospital, in order to avoid medication error, it is vital that staff are made aware of the type of insulin that you are on and that it is five times the strength of regular insulin. It will be necessary to keep an alert on your medical notes to raise awareness throughout your admission. Your insulin must be stored in the medication lockers adjacent to your bedside and must not be stored in the ward fridge.
It is important that you are aware that Humulin R U500 insulin is not currently licensed or manufactured in the UK but is imported from the USA.
Diabetes specialist nurse ______________________________________
Diabetes specialist dietician ____________________________________
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Cambridge University Hospitals
NHS Foundation Trust
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