TreatmentSuxamethonium apnoea is often only apparent at the end of an operation. These patients may remain paralysed for up to several hours after a standard dose of suxamethonium. They are kept anesthetised and ventilated in a high dependency unit until this muscle relaxant is cleared by other slower means and the patient begins breathing spontaneously. The length of support will depend on the defect in the cholinesterase phenotype/genotype.