Interactions with Anticholinesterases

Another interaction with succinylcholine involves neostigmine or pyridostigmine. For example, after dTc has been used for intra-abdominal surgery of long duration and the neuromuscular blockade has been reversed by neostigmine, the surgeon announces that another 15 minutes is needed to retrieve a missing sponge. Succinylcholine should not be administered to reestablish neuromuscular blockade because it produces relaxation that will last up to 60 minutes when given soon after the administration of neostigmine (5 mg). Sunew and Hicks^[77] found that the effect of succinylcholine (1 mg/kg) was prolonged from 11 to 35 minutes when it was given 5 minutes after the administration of neostigmine (5 mg). Such prolongation can partly be explained by inhibition of butyrylcholinesterase by neostigmine. Ninety minutes after neostigmine administration, butyrylcholinesterase activity returned to less than 50% of its baseline value.