Suplha drugs

Last night I had a patient who had an allergy to “sulpha” drugs. When we gave him IV morphine (as morphine sulphate) he got a mild rash up his arm around the injection site. This lead to a debate as to whether morphine sulphate was a sulpha drug.

It is not.

sulphonamide functional group

Sulpha drugs are drugs which has a sulphonamide functional group. Drugs that have sulphate or sulphite groups are not sulpha drugs. That includes morphine sulphate, in fact, anything –sulphate is not a sulpha drug.

The only drug likely to be used in the pre-hospital arena that is a sulphonamide drug is frusemide, a diuretic. Other drugs in the class include celecoxib, a NSAID and acetazolamide, an anti-convulsant. Some anti-microbrials are sulphonamide-based, lile sulfisomidine.

So, the moral of this post is that as a pre-hospital care provider, there is no reason to worry about causing a sulphonamide reaction as part of your treatment.