Issues for Surgery
Potentially irreversible decline in cognitive function if stopped (see Further Information).
Interaction with neuromuscular blocking drugs (NMBDs) if continued (see Interaction(s) with Common Anaesthetic Agents).
Advice in the Perioperative period
Elective and Emergency Surgery
Ensure Anaesthetist is aware of drug interactions.
Consider the following: -
Restart as soon as possible post-operatively.
Interaction(s) with Common Anaesthetic Agents
Neuromuscular Blocking Drugs (NMBDs)
Neostigmine may be ineffective as a reversal agent due to the pre-existing level of cholinesterase inhibition; furthermore, administration of neostigmine could potentiate the effect through a phase II depolarising block with suxamethonium1,4,5. Neostigmine should be used with caution in patients taking donepezil5.
Case reports provide support for these interactions4, 5, 6.
Donepezil can increase the risk of bradycardia when used concomitantly with the following2: -
Interaction(s) with other Common Medicines used in the Perioperative Period
None2, 3, 4.
Rationale for Continuing Pre-operatively
Manufacturer’s advice is to stop donepezil 2-3 weeks pre-operatively in view of its 70 hour elimination half-life1. However, clinical trials have shown that a treatment gap of 3 weeks resulted in loss of cognitive function which was only partially regained when treatment restarted thus reducing the long term beneficial effects of treatment7. In view of this potentially irreversible decline in cognitive function the withdrawal of donepezil 2-3 weeks before an operation cannot be supported5.
Patients with dementia are at increased risk of developing post-operative delirium. Avoiding medications with anticholinergic side effects (e.g. cyclizine) can minimise this risk1.