[Psychotic reactions during administration of quinolones].

A 86-year-old woman became psychotic one day after starting treatment with 800 mg norfloxacin daily. Discontinuation and short-term treatment with haloperidol were followed by rapid disappearance of symptoms within two days. Since 1984, the Netherlands Centre for Monitoring of Adverse Reactions to Drugs received 19 similar reports of which 12 were attributed to norfloxacin, 3 to ofloxacin and 4 to pipemidic acid. The risk appears to be relatively high in the elderly, especially if they have fever, renal dysfunction and a psychiatric history. Lowering the doses may solve this problem provided the bacterial susceptibility is taken into account.