title: A functional psychosis precipitated by quinidine.
abstract: A 62-year-old man with a syndrome of gradually progressive cognitive deterioration accompanied by paranoid features is described. He had been taking quinidine since 1974 for a recurring supraventricular tachyarrhythmia. Examination revealed a suspicious man with widespread patchy cognitive deficits but no focal neurological signs. An exhaustive range of investigations gave unremarkable results. Within 24 hours of cessation of quinidine there was a dramatic improvement in his mental state and, after a further four days, he had returned essentially to normal with no demonstrable cognitive deficits. Several months later he suffered a recrudescence with prominent paranoid and depressive features which gradually settled after commencement of pimozide and dothiepin. It is likely that these events reflect a recurring functional psychosis which was precipitated or exacerbated in the first instance by quinidine. This represents a significant complication of quinidine therapy which has been largely unrecognized. Therapy with quinidine should be considered as a potential contributing factor in any patient with dementia or a functional psychosis who is also taking this drug.
authors.affiliation: Department of Clinical Pharmacology and Toxicology, St Vincent's Hospital, Darlinghurst, NSW.
authors.forename: A G
authors.initials: AG
authors.lastname: Johnson
authors.forename: R O
authors.initials: RO
authors.lastname: Day
authors.forename: W A
authors.initials: WA
authors.lastname: Seldon
mesh_terms: D003072:Cognition Disorders / Q000139:chemically induced; D004334:Drug Administration Schedule; D006801:Humans; D008297:Male; D008875:Middle Aged; D010258:Paranoid Behavior / Q000139:chemically induced; D011605:Psychoses, Substance-Induced / Q000209:etiology*; D011802:Quinidine / Q000008:administration & dosage / Q000009:adverse effects*; D012008:Recurrence; D013617:Tachycardia, Supraventricular / Q000188:drug therapy
chemical_list: D011802:Quinidine