Prescribing-label excerpts
Neostigmine Methylsulfate
Reference for: Neostigmine MethylSulphate. Source presentation: injection. Source route: intravenous.
Mechanism of action
Neostigmine methylsulfate is a competitive cholinesterase inhibitor. By reducing the breakdown of acetylcholine, neostigmine methylsulfate induces an increase in acetylcholine in the synaptic cleft which competes for the same binding site as nondepolarizing neuromuscular blocking agents, and reverses the neuromuscular blockade.
Pharmacokinetics
Distribution: Following intravenous injection, the observed neostigmine methylsulfate volume of distribution is reported between 0.12 and 1.4 L/kg. Protein binding of neostigmine methylsulfate to human serum albumin ranges from 15 to 25%.
Metabolism: Neostigmine methylsulfate is metabolized by microsomal enzymes in the liver.
Elimination : Following intravenous injection, the reported elimination half-life of neostigmine methylsulfate is between 24 and 113 minutes. Total body clearance of neostigmine methylsulfate is reported between 1.14 and 16.7 mL/min/kg.
Renal impairment: Elimination half-life of neostigmine methylsulfate was prolonged in anephric patients compared to normal subjects; elimination half-life for normal, transplant and anephric patients were 79.8 ± 48.6, 104.7 ± 64 and 181 ± 54 min (mean ± SD), respectively.
Hepatic impairment: The pharmacokinetics of neostigmine methylsulfate in patients with hepatic impairment has not been studied.
Pediatrics: Elimination half-life of neostigmine methylsulfate in infants (2 to 10 months), children (1 to 6 years) and adults (29 to 48 years) were 39 ± 5 min, 48 ± 16 min, and 67 ± 8 min (mean ± SD), respectively. Observed neostigmine methylsulfate clearance for infants, children and adults were 14 ± 3, 11 ± 3 and 10 ± 2 mL/min/kg (mean ± SD), respectively.
Drug Interaction Studies: The pharmacokinetic interaction between neostigmine methylsulfate and other drugs has not been studied.
Selected passages from the cited U.S. prescribing label. The studies concern the source product and populations named in each passage; they do not establish Walter-product bioequivalence, an approved indication, or the kinetics of another fixed combination. Tables and the full prescribing information remain available in the source.
Source: DailyMed: Neostigmine Methylsulfate — injection
Reference accessed . Label revision: 2026-06-18.
