Neostigmine: Side Effects
Basic, Organ-Based and Clinical Sciences
When neostigmine is administered to reverse neuromuscular blockade, the nicotinic effects are desired but muscarinic effects can be problematic.
- Muscarinic effect results in bradycardia by slowed conduction through AV node
- Must be dosed in combination with glycopyrrolate, which is vagolytic and has a similar onset of effect.
- Hypotension secondary to decreased in peripheral vascular resistance
Nausea and Vomiting
- Conflicting studies with some reporting increased nausea and vomiting, some with antiemetic effect, and others showing no difference.
- Meta-analysis by Tramer and Fuchs-Bader of 1100 patients showed incidence of vomiting in 17-33% and dose-dependent relationship between neostigmine and PONV
- Bronchospasm due to cholinergic effect
- Hypoxia and increased secretions
· Miosis, increased GI secretions and motility, possible NMB at high doses
Side effects must be carefully balanced against the potential for residual weakness if patient does not have neuromuscular blockade antagonized