Ciprofloxacin-Induced Psychosis

To the Editor: Ciprofloxacin is a broad-spectrum, bactericidal antibiotic of the fluoroquinolone group that is well-tolerated in adult population. Ciprofloxacin acts through binding two of the four topoisomerases of bacteria.¹ Its common adverse effects include nausea, vomiting, diarrhea, abdominal discomfort, dizziness, headache, and rashes.² Rarely, neuropsychiatric adverse effects such as psychosis occur with ciprofloxacin.³ We report on an acute psychosis that developed in a patient treated with ciprofloxacin for gastroenteritis and which resolved spontaneously after discontinuation.

Case Report

“Ms. A,” a 22-year-old single woman presented with fever, diarrhea, and vomiting of 1 day’s duration, suggestive of acute gastroenteritis, for which she received ciprofloxacin infusion 100 mg bid for 3 days, followed by oral ciprofloxacin 250 mg bid for 3 more days, along with supportive treatment. There was improvement in her gastrointestinal symptoms with treatment, but she developed fearfulness, psychomotor retardation, episodes of visual and auditory hallucinations, and poor self-care. These symptoms resolved within 2 to 3 days without any additional intervention. Investigations including complete blood count, electrolytes, liver and renal function tests, and blood sugar were within normal range. Her birth and developmental history was unremarkable. There was no past or family history of any psychiatric illness. Premorbidly, she was well adjusted. Based on the Naranjo ADR Probability Scale⁴ score of 6, we considered a probable diagnosis of ciprofloxacin-induced psychosis.

Discussion

There are only few cases of psychosis reported with oral ciprofloxacin,^5–11 and rarely with topical preparation.¹² In all the reported cases, onset was early after administration of ciprofloxacin, and remission occurred with medication discontinuation. Psychosis has also been reported with other fluoroquinolones, such as norfloxacin,¹³ ofloxacin,^14,15 levofloxacin,¹⁶ and gatifloxacin.^17,18 The clinical manifestations in the reported cases are paranoid-hallucinatory type, as noted in our case. There is only one report of mania associated with ciprofloxacin.¹⁹

The mechanism of psychosis with fluoroquinolones is not known. It has been suggested that psychosis occurs through alteration of glutamatergic neurotransmission.¹¹ The anecdotal reports suggest psychosis as an uncommon adverse effect with fluoroquinolones. Nevertheless, it would be prudent to consider drug-induced psychosis as a possibility when acute onset behavioral changes are associated with use of these medications.