Safe Use of Alfentanil Injection (in palliative care)
Alfentanil is an injectable strong opioid which is 30 times more potent than oral morphine. It is used, following specialist advice, for moderate to severe opioid responsive pain in palliative patients with stage 4-5 chronic kidney disease (eGFR <30ml/min/1.73m2), or severe acute renal impairment (see Scottish Palliative Care Guideline on alfentanil for other indications). It is administered as single subcutaneous injections or as a continuous subcutaneous infusion via a syringe pump. The potential risks with injectable alfentanil, and associated good practice points to reduce any risk, are outlined below:
Potential risks
1. Wide dose range
Alfentanil can be prescribed over a wide dose range. Consequently doses may be written in MICROgrams or MILLIgrams leading to prescribing or administration errors.
Example of a low dose: 200microgram subcutaneous alfentanil for an opioid- naïve patient (equivalent to 3mg of subcutaneous morphine)
Example of a high dose: 10mg subcutaneous alfentanil for severe opioid-responsive pain (equivalent to 150mg of subcutaneous morphine or 300mg oral morphine)
2. Strengths of injection
The following two strengths of alfentanil injection are available and packaging can be similar:
- 500micrograms/mL - presented as a 1mg/2ml ampoule
- 5mg/mL (TEN times stronger) – presented as a 5mg/1ml ampoule
Due to the wide dose range, an individual clinical area may be caring for a patient requiring the low strength injection and a patient requiring the high strength injection. Stock of both strengths increases the risk of incorrect product selection and subsequent administration of an incorrect dose.
3. Similar sounding drug names
Alfentanil is similar sounding to fentanyl and mix-ups have previously been reported with both drugs. As fentanyl is four times more potent than alfentanil, the clinical consequences of a mix-up error would be significant.
Practice points
1. For palliative care dosing advice refer to the Scottish Palliative Care Guideline on alfentanil
2. To reduce the risk of misreading the dose of alfentanil (or any other medicine):
a) Do not abbreviate the word micrograms (it is acceptable to abbreviate the word milligrams to mg)
b) Always prescribe doses less than 1mg in micrograms rather than milligrams
c) Where possible, avoid using a decimal point. If a decimal point is required to be used, good practice is to write the dose in words as well as figures.
3. Training on the prescribing, preparation, administration and dispensing of injectable medicines must emphasise the difference between micrograms and milligrams i.e. 1000micrograms equals 1milligram
4. Stop and check that the box you pick up is:
a) the right medicine
b) the right strength
5. A fully independent second check is essential for the preparation of all injectable medicines
6. If both strengths of alfentanil injection are required then:
a) Store separately in the CD cupboard
b) Return the high strength (5mg/ml) preparation to pharmacy as soon as possible; as alfentanil is a controlled drug, your local pharmacy team must be contacted to arrange uplift or destruction.
(Adapted from Controlled Drugs National Group Joint Sub-Groups Newsletter - September 2017 provided by the London Opioid Safety & Improvement Group)
Published 24/12/19. Medicines Update blogs are correct at the time of publication.