Neostigmin

Neostigmine (Syntostigmin)

Mechanism of action

Cholinesterase inhibitor (indirect-acting parasympathomimetic).

Reversibly inhibits acetylcholinesterase which, as a result, increases the amount of acetylcholine. This way neostigmine indirectly stimulates nicotinic and muscarinic receptors and acts as parasympathomimetic. 

Is used as an antagonist to non-depolarizing neuromuscular blockers. For this indication, atropine should be administered concomitantly to prevent undesirable cholinergic reactions.

Indications and dose

Pharmacokinetics

Onset of action: within 1 minute

Duration of action: 20–30 min

Half-life of elimination: 52 minutes

Metabolism: Hydrolysis by cholinesterase, partly hepatic

Elimination: Kidneys

Directions for administration

Administer IV, IM or SC.

When given intravenously, neostigmine should be administered slowly (over 1 minute).

A syringe of atropine should be prepared to counteract severe cholinergic reactions.

Medicinal forms

Solution for injection (0.5 mg/ml)

1 vial = 1 ml (0.5 mg)

Side-effects

Cholinergic syndrome

Bradycardia, decreased cardiac conduction

Hypotension

Increased bronchial secretion, bronchospasm

Nausea, vomiting, diarrhoea

Muscle spasms

Miosis

Increased lacrimation and salivation

Reversal

1–4 mg of atropine sulfate should be administered intravenously in a case of cholinergic crisis.

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References

1. Neostigmine Methylsulfate Injection BP 2.5mg in 1ml - Summary of Product Characteristics (SmPC) - (emc) (medicines.org.uk)
2. Neostigmine Dosage Guide + Max Dose, Adjustments - Drugs.com
3. Anticholinesterases and anticholinergic drugs | BJA Education | Oxford Academic (oup.com)
4. Neostigmine: Uses, Interactions, Mechanism of Action | DrugBank Online
5. Atropine sulfate 0.5 mg/5 ml, solution for injection in pre-filled syringe - Summary of Product Characteristics (SmPC) - (emc) (medicines.org.uk)