Related Experiment Video
Updated: Jul 14, 2026

Rating L-DOPA-Induced Dyskinesias in the Unilaterally 6-OHDA-Lesioned Rat Model of Parkinson's Disease
Published on: October 4, 2021
Prolonged anticholinergic delirium following antihistamine overdose
James Scott1, David Pache, Greg Keane
1Mater Kids in Mind Inpatient Unit, Mater Children's Hospital, South Brisbane, Qld., Australia. james.scott@mater.org.au
Objective:
A case of anticholinergic delirium in a female adolescent is described, exploring the pharmacokinetic reasons for the prolonged time course and reviewing the management provided.
Conclusion:
A 14 year old female hospitalised for depression ingested large quantities of promethazine and cyproheptadine. A severe anticholinergic delirium ensued which resolved after six days, much longer than the expected duration. The likely cause of the prolonged delirium was the interaction of promethazine and fluvoxamine through the inhibition of the CYP2D6 enzyme. The patient's young age, the severity of the poisoning and the use of drugs with anticholinergic properties to manage the delirium may also have contributed. The delirium may have been reversed had a cholinesterase inhibitor been provided soon after the overdose.
More Related Videos
Related Concept Videos
Anticholinesterase Agents: Poisoning and Treatment
Irreversible agents form a strong bond with the cholinesterase enzyme, making it inactive. The breakdown of the phosphorylated enzyme is slower than the...
Toxidromes: Clinical Features
Indirect-Acting Cholinergic Agonists: Pharmacological Actions
At the neuromuscular junction, these agents work by inhibiting the breakdown of acetylcholine, allowing it to remain bound to the receptor and bind to nearby receptors. This process leads to repetitive firing of the endplate, causing muscle...
Indirect-Acting Cholinergic Agonists: Pharmacokinetics
Reversible agents containing quaternary amines, such as neostigmine and edrophonium, are not easily absorbed orally because they are...
Chemotherapy-Induced Nausea and Vomiting: Dopamine Receptor Antagonists
Phenothiazines, such as prochlorperazine...
Direct-Acting Cholinergic Agonists: Pharmacokinetics

