Local Anaesthetics and Children - Part 1
WHAT TO USE & HOW MUCH
A crucial part of providing high-quality and predictable paediatric dental care is mastering local anaesthetic in children. We are going to try and summarise its use in paediatric dentistry and provide an overview of some safety information. This will be broken over two posts.
Do Kids Need Local?
You would be surprised at the number of children paediatric dentists see every year that have had painful and invasive dental procedures completed without local anaesthetic. If these procedures were performed on adults, there would be no question as to whether they needed (or were offered) local anaesthetic.
Generally, dental practitioners that are reluctant to use local anaesthetic in children report that giving a ‘needle’ is scarier than just drilling quickly and getting the job done.
Commonly however, this results in either a compromised procedure (for example no rubber dam use, or a GIC bog) and a broken and distrustful child. As such, we STRONGLY recommend that any procedure that will (or is likely to) result in pain, needs to be performed under local anaesthetic. We would go as far as saying an invasive procedure performed on a child without local anaesthetic is child abuse.
Most kids in our experience tolerate the procedure to give local anaesthetic much better than the actual dental procedure itself. So, in summary if it will hurt USE LOCAL ANAESTHETIC.
General Safety
Children are commonly deemed ‘pharmacological orphans’ due to the lack of high-quality research on the use of medications in the paediatric population. Sadly, local anaesthetics also fall into this category.
However, we can provide a summary of general safety information
Children can be overdosed on local (and topical) anaesthetic
There is insufficient knowledge for <4yrs for local anaesthetic dosages and safety
o For example. New Zealand does not recommend Lignocaine <3 years
o Manufactures of Articaine state it is not safe for use <4 years
Methemoglobinemia is the main risk with certain anaesthetic agents
o Primarily reported with Prilocaine (ester) and Benzocaine (ester)
o Results in hypoxia due to a complex process that disables the oxygen carrying capacity of red blood cells. It is a medical emergency.
Relative caution is required in
o Poorly controlled and severe cardiovascular disease,
o Diabetes,
o Thyroid disorders.
Vasoconstrictors (VC) should be avoided, or used with caution in certain patients:
o Patients with sulfate (sulfite) allergy – it is the preservative for the VC
o Patients taking: Monoamine oxidase inhibitors, tricyclic antidepressants, antipsychotic drugs, norepinephrine, or phenothiazines
o Without it however, you will have reduced efficacy and will get quick systemic absorption
Teething Gels
When discussing local anaesthetic and the paediatric population, it would be remiss of us not to discuss teething gels. Most teething gels have either a topical anaesthetic agent in them, or a pain-relieving agent such as Choline Salicylate.
These gels can easily be overdosed in a young infant and should be strongly discouraged! The FDA has for several years recommended against their use.
Furthermore, when we place topic anaesthetic, it requires a few minutes contacting fry mucosa to be effective. I don’t know any 9-month old that would let you hold some bonjela on dry mucosa for long enough to be effective (we know as we have a 9-month old)
Furthermore, we do not give children under the age of 16 years Aspirin due to the risk of Reye’s Disease. However, Bonjela, has Choline Salicylate as its main pain relief ingredient. This is linked to Salicylate Acid which is Aspirin. It is actually mind-boggling that this was commonly sold and recommended for use in children for many years in Australia.
So, what can you do… We have a child that is going through this now and we recommend Panadol and Ibuprofen as required, cold toys to suck on and some stiff coffees to get through the day!
Topical Anaesthetics (TA)
Topical anaesthetics are crucial to allow you to deliver local more effectively. The main topical anaesthetics used in Australia include:
5% or 10% Lignocaine ointment – this is the most common in Australia
20% Benzocaine gel - this is more commonly used in North America.
Compounded gel called TAC 20%. This has 20% Lignocaine, 4% Tetracaine 2% Adrenaline
The concern with benzocaine is the risk of methemoglobinemia and their ester containing components. Esters have an increased risk of an allergy compared to amide anaesthetics. TAC gel is reported to provide superior anaesthetic to other formulations but can be easily overdosed. It also requires a compounding pharmacy and a script. As such, the most commonly used TA is 5 or 10% Lignocaine.
Local Anaesthetics agents
There are two main local anaesthetic agents used in Paediatric Dentistry; Lignocaine and Articaine. Mepivacaine is also used in cases where a vasoconstrictor is contraindicated, however, we have so rarely used this, we will not review it further.
There have been some comparisons between Lignocaine and Articaine for efficacy. There is inconclusive evidence as to which is superior for infiltrations, with some limited evidence that Articaine is super for inferior alveolar nerve blocks.
Anecdotally, we find that Articaine is superior to achieve anaesthesia when placed as an infiltration. In the next post we will discuss which procedures we use Lignocaine for and which we use Articaine for and why.
Maximum Dosages
You can overdose a patient on local anaesthetic and as children are so small, this can easily occur. As such, it is important to know how much local anaesthetic is safe to give. The guidelines for the maximum dosage in mg/kg do seem to differ between countries and nation states.
We tend to stick to the more conservative measure for most paediatric dental procedures. This is as you should not be getting anywhere near the maximum dosage in everyday dentistry.
Maximum Dosages include (we have used the AAPD standards):
Articaine 4% + 1:100,000Ad
o 7mg/kg
Lignocain 2% + 1:80,000Ad
o 4.4mg/kg
Mepivacaine 3% (plain)
o 6.6mg/kg
An easy way to work out the amount you can give for the child’s weight
Summary
This first blog dealt with an overview of the safety of anaesthetics in children and how much you can give. In the next month’s blog, we will look at what we use when and how we predictably and reliably give local anaesthetic in children.
We hope this all helps.
Sarah and Tim