Frequently Asked Questions
1. Is there another muscle relaxant which is metabolised by cholinesterase?
Yes and it is called mivacurium. This drug is also metabolised by cholinesterase but unlike suxamethonium it is a competitive inhibitor for the neurotransmitter acetylcholine. Although the effect of this drug can be more easily reversed, mivacurium should also be avoided in individuals with low enzyme levels and/or atypical cholinesterase phenotypes.
2. Are there alternative muscle relaxants which can be used?
Yes, there is a range of other muscle relaxants which are available for use in surgical operations.
3. What happens if I have experienced Suxamethonium Apnoea?
A blood sample will be taken to measure the total cholinesterase activity and frequently the enzyme phenotype. If the results show that the enzyme level is low or low normal and an abnormal or silent phenotype is present this should be recorded in your notes. In some cases this may include a genotype study. In addition you should be given a Medical Warning card giving your cholinesterase details so that it may be shown to a surgeon and anaesthetist before any future surgical operations.
4. What happens if a close relative experiences Suxamethonium Apnoea?
If a close relative such as a parent, brother, sister or child is affected in this way after some surgery and found to have an abnormal or silent cholinesterase phenotype, then family members should be offered blood tests to see if they are carrying the same phenotype or genotype. If this is the case they will also be encouraged to carry similar medical warning cards.