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Quick facts
- How it is given
- intravenous
- Type
- human prescription drug
- RxNorm ID
- 311936
We do not publish dosing. How much of this medicine to take, how often, and for how long depends on your age, weight, kidney and liver function, other conditions and other medicines. That is a decision for the person who prescribes or dispenses it. Follow the directions on your own pack and ask your pharmacist if anything is unclear.
What it is used to treat
Neostigmine Methylsulfate Injection, a cholinesterase inhibitor, is indicated for reversal of the effects of nondepolarizing neuromuscular blocking agents (NMBA) after surgery. Neostigmine Methylsulfate, a cholinesterase inhibitor, is indicated for reversal of the effects of nondepolarizing neuromuscular blocking agents (NMBA) after surgery ( 1 ).
About this medicine
Neostigmine Methylsulfate Injection, USP, a cholinesterase inhibitor, has an empirical formula of C 13 H 22 N 2 O 6 S, a molecular weight of 334.39 g/mol and the following structural formula: Neostigmine Methylsulfate Injection is formulated with neostigmine methylsulfate, a white crystalline powder, chemically designated as (m-hydroxyphenyl) trimethylammonium methylsulfate dimethylcarbamate. Neostigmine Methylsulfate Injection, USP is available in two dosage strengths; 0.5 mg/mL, and 1 mg/mL in 10 mL multiple dose amber glass vials. The composition per mL is as follows: Ingredients mg/mL Neostigmine Methylsulfate 0.5 1 Phenol (as Liquefied Phenol, USP) 4.5 4.5 Sodium Acetate, USP (Trihydrate) 0.2 0.2 Water for Injection q.s. q.s Phenol is added as a preservative. Acetic acid and/or sodium hydroxide may have been added for pH adjustment. structure
How it works
12.1 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.
Who should not take it
Neostigmine is contraindicated in patients with: known hypersensitivity to neostigmine methylsulfate (known hypersensitivity reactions have included urticaria, angioedema, erythema multiforme, generalized rash, facial swelling, peripheral edema, pyrexia, flushing, hypotension, bronchospasm, bradycardia and anaphylaxis). peritonitis or mechanical obstruction of the urinary or intestinal tracts. Hypersensitivity to neostigmine ( 4 ) Peritonitis or mechanical obstruction of urinary or intestinal tracts ( 4 )
Warnings and cautions
Bradycardia : Atropine or glycopyrrolate should be administered prior to administration of neostigmine methylsulfate injection to lessen risk of bradycardia ( 5.1 ) Coexisting Conditions : patients with known cardiac disease, cardiac arrhythmias, or recent coronary artery occlusion may be particularly sensitive to the hemodynamic effects of neostigmine; their blood pressure and electrocardiogram should be continuously monitored with the initiation of neostigmine treatment and for a duration sufficient to assure hemodynamic stability. ( 5.2 ) Neuromuscular Dysfunction : Can occur if large doses of neostigmine methylsulfate are administered when there is minimal neuromuscular blockade; reduce the dose if recovery from neuromuscular blockade is nearly complete. ( 5.4 ) 5.1 Bradycardia Neostigmine has been associated with bradycardia. An anticholinergic agent, (e.g., atropine sulfate or glycopyrrolate) should be administered prior to Neostigmine Methylsulfate Injection administration to lessen the risk of bradycardia [ see Dosage and Administration ( 2.4 ) ]. 5.2 Cardiovascular Complications Cardiac arrhythmias, nonspecific electrocardiogram changes, cardiac arrest, syncope and hypotension have been reported with neostigmine methylsulfate. In patients with certain cardiovascular conditions such as coronary artery disease, cardiac arrhythmias or recent acute coronary syndrome, the risk of blood pressure and heart rate complications may be increased. Risk of these complications may also be increased in patients with myasthenia gravis. Standard antagonism with anticholinergics (e.g., atropine) is generally successful to mitigate the risk of cardiovascular complications. 5.3 Hypersensitivity (Anaphylaxis) Hypersensitivity reactions including anaphylaxis have been reported with neostigmine. Ensure that appropriate medical support measures, including atropine, cardiopulmonary resuscitation equipment, and medications to treat anaphylaxis are readily available. 5.4 Neuromuscular Dysfunction Neuromuscular dysfunction has been associated with administration of large doses of neostigmine when neuromuscular blockade is minimal. […]
Reported side effects
The most common adverse reactions include bradycardia and nausea and vomiting. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Fresenius Kabi USA, LLC at 1-800-551-7176 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trial Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The following serious adverse reactions are described below and elsewhere in the labeling: Bradycardia [ see Warnings and Precautions ( 5.1 ) ] Cardiovascular Complications [ see Warnings and Precautions ( 5.2 ) ] Hypersensitivity (Anaphylaxis) [ see Warnings and Precautions ( 5.3 ) ] Adverse reactions to neostigmine methylsulfate are most often attributable to exaggerated pharmacological effects, in particular, at muscarinic receptor sites. The use of an anticholinergic agent, e.g., atropine sulfate or glycopyrrolate, may prevent or mitigate these reactions. Quantitative adverse event data are available from trials of neostigmine methylsulfate in which 200 adult patients were exposed to the product. Adverse reactions that occurred with an overall frequency of 1% or greater included the following: Allergic: Allergic reactions and anaphylaxis. Neurological: Dizziness, syncope, weakness, convulsions, loss of consciousness, drowsiness, headache, dysarthria, miosis and visual changes. Cardiovascular: Cardiac arrhythmias including bradycardia, tachycardia, atrioventricular block and nodal rhythm, as well as cardiac arrest, and hypotension. Respiratory: Increased oral, pharyngeal and bronchial secretions, dyspnea, respiratory depression, oxygen desaturation, respiratory arrest and bronchospasm. Dermatologic: Diaphoresis, flushing, rash, pruritus, and urticaria. Gastrointestinal: Dry mouth, nausea, emesis, flatulence and increased peristalsis. Genitourinary: Increased urinary frequency. Musculoskeletal: Muscle cramps and spasm, arthralgia. […]
Interactions with other medicines
The pharmacokinetic interaction between neostigmine methylsulfate and other drugs has not been studied. Neostigmine methylsulfate is metabolized by microsomal enzymes in the liver. Closely monitor patients for a longer period of time when using Neostigmine Methylsulfate Injection with other drugs which may alter the activity of metabolizing enzymes or transporters. 7.1 Depolarizing Muscle relaxants Use of neostigmine to reverse the effects of depolarizing muscle relaxants such as succinylcholine is not recommended, because it may prolong the phase-1 block. 7.2 Antibiotics Certain antibiotics, particularly neomycin, streptomycin and kanamycin have nondepolarizing neuromuscular blocking action, and therefore, neostigmine dose adjustments may be required to reverse neuromuscular block in patients who have been taking these drugs. There was no effect on neostigmine action on rocuronium reversal by cefuroxime, metronidazole, cefuroxime or metronidazole.
Use in specific groups
Pregnancy: No human data and limited animal exist. Use only if clearly needed. 8.1 Pregnancy- Risk Summary There are no adequate or well-controlled studies of Neostigmine Methylsulfate Injection in pregnant women. It is not known whether Neostigmine Methylsulfate Injection can cause fetal harm when administered to a pregnant woman or can affect reproductive capacity. The incidence of malformations in human pregnancies has not been established for neostigmine as the data are limited. All pregnancies, regardless of drug exposure, have a background risk of 2 to 4% for major birth defects, and 15 to 20% for pregnancy loss. No adverse effects were noted in rats or rabbits treated with human equivalent doses of neostigmine methylsulfate doses up to 8.1 and 13 mcg/kg/day, respectively, during organogenesis (0.1 to 0.2-times the maximum recommended human dose of 5 mg/60 kg person/day based on body surface area comparisons). Anticholinesterase drugs, including neostigmine may cause uterine irritability and induce premature labor when administered to pregnant women near term. Neostigmine Methylsulfate Injection should be given to a pregnant woman only if clearly needed. Data Animal Data In embryofetal development studies, rats and rabbits were administered neostigmine methylsulfate at human equivalent doses (HED, on a mg/m 2 basis) of 1.6, 4 and 8.1 mcg/kg/day 3.2, 8.1, and 13 mcg/kg/day, respectively, during the period of organogenesis (Gestation Days 6 through 17 for rats and Gestation Days 6 through 18 for rabbits). There was no evidence for a teratogenic effect in rats and rabbits up to HED 8.1 and 13 mcg/kg/day, which are approximately 0.097-times and 0.16-times the MRHD of 5 mg/60 kg, respectively in the presence of minimal maternal toxicity (tremors, ataxia, and prostration). The studies resulted in exposures in the animals well below predicted exposures in humans. In a pre- and postnatal development study in rats, neostigmine methylsulfate was administered to pregnant female rats at human equivalent doses (HED) of 1.6, 4 and 8.1 mcg/kg/day from Day 6 of gestation through Day 20 of lactation, with weaning on Day 21. […]
If too much is taken
Muscarinic symptoms (nausea, vomiting, diarrhea, sweating, increased bronchial and salivary secretions, and bradycardia) may appear with overdosage of neostigmine methylsulfate, but may be managed by the use of additional atropine or glycopyrrolate. The possibility of iatrogenic overdose can be lessened by carefully monitoring the muscle twitch response to peripheral nerve stimulation. Should overdosage occur, ventilation should be supported by artificial means until the adequacy of spontaneous respiration is assured, and cardiac function should be monitored. Overdosage of neostigmine may also cause a cholinergic crisis, which is characterized by increasing muscle weakness, and through involvement of the muscles of respiration, may result in death if not promptly treated. The treatment of an overdose of neostigmine includes immediate withdrawal of all anticholinergic medication and immediate use of atropine is also recommended. Assistance of ventilation may be required if respiration is severely depressed. Myasthenic crisis, due to an increase in the severity of the disease, is also accompanied by extreme muscle weakness and may be difficult to distinguish from cholinergic crisis on a symptomatic basis. However, such differentiation is extremely important because increases in the dose of neostigmine methylsulfate or other drugs in this class, in the presence of cholinergic crisis or of a refractory or “insensitive” state, could have grave consequences. The two types of crises may be differentiated by the use of edrophonium chloride as well as by clinical judgment. Treatment of the two conditions differs radically. Whereas the presence of myasthenic crisis requires more intensive anticholinesterase therapy, cholinergic crisis calls for the prompt withdrawal of all drugs of this type. The immediate use of atropine in cholinergic crisis is also recommended. Atropine may also be used to lessen gastrointestinal side effects or other muscarinic reactions; but such use, by masking signs of overdosage, can lead to inadvertent induction of cholinergic crisis.
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This page is built from the openFDA record of the U.S. Food and Drug Administration's approved labelling for this product, effective 22 January 2024. Label text has been shortened and reformatted for readability; safety wording has not been altered in meaning. FDA labelling describes products approved in the United States — brand names, strengths, formulations and approved uses may differ in your country. Always read the leaflet that comes with your own pack. PocketsInfo is not affiliated with, and is not endorsed by, the FDA. Retrieved 2026-07-30.