In March this year, some insulin pens became available on National Health Service prescription. The decision to use a particular type of pen is based on the individual needs of the patient and is made following discussion between the patient and doctor or diabetic nurse. Pens can either be prefilled or used with insulin cartridges and are available in two sizes.
Table 1 indicates which pens are now available on prescription. It also gives information about the type and size of insulin cartridge that each pen takes.
Table 1: types of insulin pen |
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| Name of pen | Availability | Insulin type | Cartridge size | Needle type | Pen manufacturer |
| Autopen (single unit dial up) |
On prescription | Any type | 1.5ml | Any type | Owen Mumford |
| Autopen (double unit dial up) |
On prescription | Any type | 1.5ml | ||
| Autopen | On prescription | Lilly cartridges | 3ml | ||
| BD pen | Not on prescription | Any type | 1.5ml | Any type | Becton Dickinson |
| BD pen | Not on prescription | Lilly Humalog and Humulin cartridges | 3ml | ||
| BD pen ultra | On prescription | Any type | 1.5ml | ||
| BD pen ultra | On prescription | Lilly Humalog and Humulin cartridges | 3ml | ||
| Humapen ergo | Not on prescription | Any Lilly Humulin cartridge | 3ml | BD Microfine + needles recommended (but see notes above) | Eli Lilly |
| Humaject | On prescription | Prefilled - Lilly Humulin S, I, M1, M2, M3, M4 (not M5) | 3ml | ||
| Humalog Mix 25 | On prescription | Prefilled - Lilly Humalog Mix 25 | 3ml | ||
| Novopen classic | On prescription | Novo Nordisk penfill cartridges | 3ml | Novofine needles recommended (but see notes above) | Novo Nordisk |
| Novopen demi | On prescription | Novo Nordisk penfill cartridges | 3ml | ||
| Novopen fun | On prescription | Novo Nordisk penfill cartridges | 3ml | ||
| Novo Nordisk pre-filled pen | On prescription | Prefilled (Novo Nordisk) - Human Actrapid, Human Insulatard, Human Mixtard 10, 20, 30, 40, 50 | 3ml | ||
| Optipen | Not on prescription | Insuman (Aventis) | 3ml | Penfine needles (Disetronic) only | Aventis Pharma |
Pen needles also became available on prescription in March. Different lengths and gauges (widths) of needles are available. Diabetes UK (formerly the British Diabetic Association) says that any needle can be used with any pen, with the exception of the Optipen which must be used with Penfine needles (manufactured by Disetronic). However, some other pen manufacturers recommend that only certain needles are used with their pens. This is indicated in Table 1.
Prescriptions may not always give the exact specifications for the needles required. Therefore, it is essential for pharmacists to be aware of the differences between types of needle and to liaise with the patient and, if necessary, the doctor, to ensure that the correct needles are dispensed. Different sizes of insulin pen needle are distinguishable by the colour of their packaging. It is important for pharmacists to know these colours because patients may often be more aware of the colour of packaging than the length and gauge of the needle.
In general, longer needles are used by patients with more body fat at the injection site. Shorter needles are used by people with less body fat at the injection site. This is to ensure that the insulin is injected into the subcutaneous tissue below the fat layer but above the muscle layer. The type of injection technique used can also affect the needle length required. Longer needles are used when patients pinch the skin and shorter needles when they do not.
The width of a needle is also a consideration because some patients prefer narrower needles as they may be more comfortable to use. Diabetes UK says that the differences in gauges are not as important as the differences in length.
The Drug Tariff (June 2000) currently lists three pharmaceutical companies as approved manufacturers of needles for pre-filled and reusable pens. These types of pen needle, and the colour of their packaging, are listed in Table 2.
Table 2: types of pen needle |
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| Name | Length | Width | Packaging colour | Manufacturer |
| BD Microfine + | 12.7mm 8mm 5mm |
29G 31G 31G |
Pink Blue Purple |
Becton Dickinson |
| Novofine | 12mm 8mm 6mm 6mm |
28G 30G 30G 31G |
Aqua/green Orange Light blue Navy blue |
Novo Nordisk |
| Unifine pentips | 8mm 12mm |
30G 29G |
Blue and yellow Pink and white |
Owen Mumford |
Mrs Bellingham is on the staff of The Pharmaceutical Journal