When operating on a conscious patient, screams of agonising pain can be distracting, and so it is generally preferable use a local anaesthetic.
In primary care minor skin surgery, fast acting lidocaine (1% or 2%) is our local anaesthetic of choice. However, in a hospital setting, it’s routine to use a mix of lidocaine with adrenaline.
Adrenaline acts as a vasoconstrictor, meaning it constricts the superficial blood vessels in the dermis. This keeps the local anaesthetic at the injection site for longer, reducing its systemic absorption.
This has several (theoretical) benefits:
The toxic dose of lidocaine is 3mg/kg. This doubles to 5-7mg/kg when you add adrenaline. Most minor skin surgery procedures will use a maximum of 3 – 4ml of local anaesthetic, and so reaching a toxic dose is unlikely, with or without adrenaline.
Lidocaine on its own lasts for about 2 hours. Using lidocaine with adrenaline can extend this to around 3 hours. This is not particularly helpful in a 20–30-minute procedure.
In practice, the primary reason most use lidocaine with adrenaline is to reduce the amount of bleeding, and to improve the overall effectiveness of the anaesthetic.
Over the last 12 months the major medical suppliers have had constant supply problems of pre-mixed 1% lidocaine with adrenaline (commonly sold as Xylocaine 1% with adrenaline, but there are other brands).
There is much speculation: some suggest hospitals are hoarding stock, or manufacturers are producing less due to low profit margins. Indeed, the latter is certainly part of the issue, as two companies have ceased production, leaving Fresenius Kabi and Pfizer as the sole remaining manufacturers.
There has also been a shortage in the supply of adrenaline, with available stocks understandably prioritised for more urgent needs.
If you’re struggling to get hold of lidocaine 1% with adrenaline, our tutors recommend the following alternatives:
Search for another source or brand
Though these alternatives brands may be unlicensed or face the same availability issues. Maintaining a good relationship with your local pharmacist can be beneficial, as they are often adept at tracking down a supply.
Forego the adrenaline
Use only lidocaine at either 1% or 2%, which will still provide an adequate anaesthetic block. Just remember the maximum toxic dose of 3mg/kg.
Use 2%
Some of our tutors have had luck sourcing 2% lidocaine with adrenaline, although this is now also in short supply.
Mix your own
Surprisingly, it’s not that complicated and just requires a bit of preparation. It’s noted that the adrenaline concentration when mixed with local anaesthetic is 1:200,000 (5mg/ml), whereas the concentration used on the resuscitation trolley is 1:10,000 (100mg/ml). One could dilute the 1:10,000 adrenaline to 1:200,000 and then add it to lidocaine. Indeed, this is a common practice in hospitals.
The Leeds Pharmacy Service has provided a very simple guide for this process: just adding 1ml of 1:10,000 adrenaline to 20ml of lidocaine 1% or 2%. Read here.
Copy the dentists
Dentists use a single-use injectable cartridge with a mix of adrenaline and lidocaine. This requires a steel syringe into which a single-use cartridge is placed. The adrenaline concentration in this is slightly different at 1:80,000, which is acceptable for use in a local anaesthetic skin block. Sold here.
The challenge here is the cost implication. The steel syringes are expensive and generally intended for sterilisation/reuse —a capability dentists have, but may not be financially viable in NHS Primary and Community Care.
It has been suggested you could insert a green needle into the dental cartridge and draw up into a normal disposable syringe. The cartridges are not designed for this though, as they require positive pressure to release their contents.
A lidocaine-adrenaline mix is a superior option in minor skin surgery, as it provides a better anaesthetic block and reduces bleeding.
However, with the current supply issues, we either need a bit of ingenuity, something primary care professionals are very familiar with, or we revert back to humble old lidocaine.
Read on to see our full course syllabus
