Neostigmine methylsulfate is available as a 0.5- or 1-mg/mL solution in 10-mL multiple-dose amber glass vials.3849 Each mL of solution contains neostigmine methylsulfate 0.5 or 1 mg, phenol 4.5 mg as a preservative, and sodium acetate 0.2 mg in water for injection.3849 Acetic acid and/or sodium hydroxide may be used to adjust the pH.3849
Neostigmine methylsulfate also may be available as a 2.5-mg/mL preservative-free injection in 1-ml ampuls with sodium chloride in water for injection.3851
pH
From 5 to 6.5.3850
Trade Name(s)
Bloxiverz
Neostigmine methylsulfate is administered by intravenous injection.3849 For certain indications, the drug also may be administered by intramuscular or subcutaneous injection.3851 Intravenous injection of the 2.5-mg/mL solution should be administered slowly over a period of at least 1 minute.3851
Neostigmine methylsulfate in intact containers should be stored at controlled room temperature and protected from light.3849; 3851
Neostigmine methylsulfate in ampuls contains no preservative and unused portions should be discarded.3851
The manufacturer of the 2.5-mg/mL solution states that the drug may be diluted with water for injection; the diluted solution should be used immediately because stability of the drug cannot be guaranteed once diluted.3851
Syringes
In 2015, reports of decreased potency of certain drugs (e.g., neostigmine methylsulfate) stored in Becton Dickinson syringes for extended periods (i.e., exceeding 24 hours) were confirmed by the manufacturer of these syringes; the cause of this change was later identified to be the inclusion of an alternate rubber stopper in the plunger of certain product lots of syringes.3029; 3036; 3037; 3039; 3041; 3042 Decreased potency was not observed when the syringes were filled and used promptly.3037 Use of the alternate stopper was later discontinued and use of the primary stopper in such syringes was resumed; however, Becton Dickinson states that its general-use syringes are cleared by FDA for immediate use in fluid aspiration and injection and that such syringes, regardless of the stopper material, have not been cleared by FDA for use as a closed-container system.3391
The stability of neostigmine 0.5 mg/mL repackaged in polypropylene syringes was evaluated. Little concentration change was found after 4 weeks of storage at room temperature not exposed to direct light.2164
Neostigmine methylsulfate (Elkins-Sinn) 0.167 mg/mL in sodium chloride 0.9% packaged in polypropylene syringes (Sherwood) was physically stable and exhibited no loss in 24 hours stored at 4 and 23°C.2199
Undiluted neostigmine methylsulfate (American Pharmaceutical Partners) 1 mg/mL was packaged in 6-mL polypropylene syringes (Becton Dickinson) and stored at 23°C in fluorescent light and at 4°C for 90 days. The drug remained physically stable and under 2% loss occurred.2425
For a list of references cited in the text of this monograph, search the monograph titled References.