What the label lists and what reports show
Neostigmine methylsulfate side effects
Neostigmine methylsulfate's FDA label: “Most common adverse reactions during treatment: bradycardia, nausea and vomiting.” FAERS holds 1,570 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is hypotension (101 reports).
- Generic listed
- A presentation discontinued
Check it at the source: the neostigmine methylsulfate FDA label on DailyMed (effective December 31, 2023, Exela Pharma Sciences, LLC); the FDA FAERS public dashboard.
What does the label list?
From the label: adverse reactionsMost common adverse reactions during treatment: bradycardia, nausea and vomiting.
From the label: adverse reactions, continuedMost common adverse reactions during treatment: bradycardia, nausea and vomiting. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Exela Pharma Sciences, LLC at 1-888-451-4321 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials 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. 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. The following table lists the adverse reactions that occurred with an overall frequency of 1% or greater.
Source: FDA drug label, Exela Pharma Sciences, LLC, effective December 31, 2023 (SPL set d2f55643-2b0d-4ef9-a9d8-b7138b314372), via openFDA; the full label on DailyMed
What do FAERS reports show?
1,570 reports list neostigmine methylsulfate among the medicines taken, each a report of something that happened, not proof the medicine caused it; 164 are coded as a death and 688 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 22 reactions below, 7 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Neostigmine methylsulfate: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions