This then presents a dilemma for the clinician in the community.
Do you prescribe the best tolerated and most effective treatment and take the risk that it will be unavailable?
Do you prescribe an alternative (soluble prednisolone) that is known to be slightly less effective and less well tolerated on the grounds that medication can only be effective if it’s actually been given?
There is also an opportunity to be proactive about the issue. You could get a member of your team to contact the local pharmacies and ask if any of them do stock liquid dexamethasone. If not, perhaps one would in which case they would be where you sent your children with croup for their treatment.
On a larger scale, primary care groups (e.g. Clinical commissioning groups in the UK) could coordinate something so that each locality has a pharmacy that stocks liquid dexamethasone.
Another way of looking at it is that there is a vicious cycle to break. Because dexamethasone is not always available, not everyone provides it. Because it is not prescribed often enough, it is not always stocked by pharmacists. More prescribing of dexamethasone should make it more likely that dexamethasone will be stocked.
It is possible that liquid dexamethasone will become a more commonly prescribed medication since it has recently been suggested that it is as effective as prednisolone for childhood wheeze. (3)
What about age banding and using soluble dexamethasone?
Dexamethasone has a large therapeutic window. The current recommended dose of 0.15mg/kg is a quarter of the dose of 0.6mg/kg which was previously the most often used dose.
This is good because age banding doses is very difficult. A four year old can be anything from 13-22kg based on the 9th-91st centiles of the WHO growth charts. Knowing the age is therefore nowhere near as good as having an actual weight. Obtaining a child’s weight does not require any special equipment. If a child will not stand on a set of scales, simply weigh an adult carrying the child and without holding the child. The difference is the child’s weight.
If using Using the 9th-91st weight centiles and aiming for a dose of 0.15-0.3mg/kg gives the following results:
The ideal is definitely to have a weight and to have a liquid suspension available that would allow the precise dose of 0.15mg/kg to be given. However, when thinking about a plan B, it seems a shame to go to Prednisolone which is known to be less effective, has more side effects and can only be given in aliquots of 5mg. Why not do the same with dexamethasone, even if it does mean that the dose may be over in some cases? Again, the therapeutic window of dexamethasone allows this to be possible.
Although liquid dexamethasone is not always on the shelves of the local pharmacy, it probably should be and possibly would be if it was more often used and the pharmacist knew that the bottle would get used.