Prolonged suxamethonium apnoea—the signal for what?

Abstract

Most cases of prolonged apnoea following suxamethonium administration are associated with pseudo-cholinesterase variant enzymes, yet an appreciable number cannot be explained on this basis. Over 50 cases of prolonged apnoea have been referred for pseudocholinesterase typing, total cholinesterase activity against benzoylcholine and the determination of dibucaine and fluoride numbers, and some 25 families have been genotyped. From this work it can be shown that: 1.Genotyping of pseudocholinesterase is important to establish whether a variant enzyme was responsible for the prolonged suxamethonium apnoea. 2.Subjects should not be told they are ‘allergic’ to suxamethonium unless supported by appropriate laboratory investigation. 3.When an enzyme variant is indicated, the proband's sibship should always be examined since similar variants are most likely to occur in the siblings. 4.Seven of the ten possible genotypes at the E1 locus have been identified including 5 cases of the homozygous state of the silent gene E18. E18. Most cases of prolonged apnoea following suxamethonium administration are associated with pseudo-cholinesterase variant enzymes, yet an appreciable number cannot be explained on this basis. Over 50 cases of prolonged apnoea have been referred for pseudocholinesterase typing, total cholinesterase activity against benzoylcholine and the determination of dibucaine and fluoride numbers, and some 25 families have been genotyped. From this work it can be shown that: 1.Genotyping of pseudocholinesterase is important to establish whether a variant enzyme was responsible for the prolonged suxamethonium apnoea. 2.Subjects should not be told they are ‘allergic’ to suxamethonium unless supported by appropriate laboratory investigation. 3.When an enzyme variant is indicated, the proband's sibship should always be examined since similar variants are most likely to occur in the siblings. 4.Seven of the ten possible genotypes at the E1 locus have been identified including 5 cases of the homozygous state of the silent gene E18. E18.