Lancaster, UK
EditorThe choice of parenteral on the label of ampoules of levobupivacaine may be questionable,1 but Abbott Laboratories should be congratulated on their choice of units to describe the concentration of the contents.
With the exception of ropivacaine, the concentrations of all available local anaesthetic solutions are described in units of per cent, meaning grams per hundred millilitres. That this is a non-SI unit, used for no other group of drugs, and unclear to new users, has apparently weighed little with manufacturers against the inertia of custom and practice. Trainees often mistake the mass of local anaesthetic drug contained in a given volume.2
Epinephrine containing ampoules of local anaesthetic are even more bizarre, in that the epinephrine concentration is quoted in yet another non-standard and misleading unit, millilitres per gram, 1 in 200 000 for instance.
The use of milligrams per millilitre for chirocaine brings this new local anaesthetic into line with most other drugs presented in solution, and should be welcomed as a positive safety factor.
J. R. Davies
Lancaster, UK
References
1 Bromhead HJ, Walker D. Potentially dangerous labelling of levobupivacaine. Br J Anaesth 2002; 88: 154
2 Scrimshire JA. Safe use of lignocaine. Br Med J 1989; 298: 1494