Potentiation of suxamethonium blockade by neostigmine in patients with atypical cholinesterase.

This report describes the potentiation of a suxamethonium-induced (0.1 mg/kg) neuromuscular block in two children with atypical serum cholinesterase activity, and compares it with a control response demonstrated in a homozygote brother. In the atypical homozygote patients, suxamethonium produced a markedly prolonged neuromuscular block associaiated with partial desensitizatin as evidenced by tetanic fade and post-tetanic facilitation. The use of neostigmine 0.05 mg/kg for reversal was followed by a paradoxical potentiation of the block and a marked delay in recovery. It is suggested that in atypical homozygotes, the development of desensitization after suxamethonium does not necessarily imply that the block will be reversed with neostigmine.