From the Guidelines
Fluoroquinolones can cause delirium due to their ability to cross the blood-brain barrier and affect the central nervous system, leading to an inhibition of GABA receptors and excessive neural excitation. The exact mechanism of delirium caused by fluoroquinolones is not fully understood, but it is thought to be related to their ability to inhibit GABA receptors in the brain, which normally have an inhibitory effect on neural activity [@1@]. When GABA receptors are blocked, excessive neural excitation can occur, leading to confusion, hallucinations, and delirium.
Key Points to Consider
- The risk of delirium is higher in elderly patients, those with kidney dysfunction, and patients taking certain medications like NSAIDs or steroids.
- The delirium typically develops within days of starting the medication and usually resolves after discontinuation.
- If a patient develops signs of delirium while taking quinolones, the medication should be stopped immediately and an alternative antibiotic considered.
Monitoring and Prevention
- Healthcare providers should use quinolones cautiously in vulnerable populations and monitor for early signs of neuropsychiatric effects such as confusion, agitation, or hallucinations.
- The study published in Pediatrics [@1@] reported neurologic adverse events, including dizziness, nervousness, insomnia, and somnolence, in patients taking ciprofloxacin, highlighting the need for careful monitoring and consideration of alternative treatments.
From the FDA Drug Label
Central Nervous System: Quinolones, including ciprofloxacin, may also cause central nervous system (CNS) events, including: nervousness, agitation, insomnia, anxiety, nightmares or paranoia. Convulsions, toxic psychoses, increased intracranial pressure (including pseudotumor cerebri) have been reported in patients receiving fluoroquinolones, including levofloxacin Fluoroquinolones may also cause central nervous system stimulation which may lead to tremors, restlessness, anxiety, lightheadedness, confusion, hallucinations, paranoia, depression, nightmares, insomnia, and, rarely, suicidal thoughts or acts.
Fluoroquinolones (FQs) may cause delirium as part of their central nervous system (CNS) effects, which can include:
- Confusion
- Hallucinations
- Paranoia These reactions may occur following the first dose of FQs, including ciprofloxacin 1 and levofloxacin 2.
From the Research
Fluoroquinolones and Delirium
- Fluoroquinolones (FQs) are known to cause central nervous system (CNS) toxicity, which can lead to delirium in some patients 3, 4, 5, 6.
- The exact mechanism of FQ-induced delirium is not fully understood, but it is thought to be related to the pharmacokinetics of FQs, their chemical structure, and their uptake in the brain 4.
- Risk factors for FQ-induced delirium include renal insufficiency, underlying CNS disease, and increased CNS penetration of the drug 5, 7.
- Delirium associated with FQs is often under-recognized and under-diagnosed, particularly in elderly patients 6.
Clinical Presentation
- FQ-induced delirium can present with a range of symptoms, including confusion, agitation, hallucinations, and psychotic features 3, 5, 6.
- The onset of delirium can be acute, and it is often reversible upon withdrawal of the offending medication 5, 6.
- Mania, insomnia, acute psychosis, and delirium are among the most frequently reported psychiatric adverse events associated with FQs 4.
Patient Populations at Risk
- Elderly patients are at increased risk of FQ-induced delirium due to age-related declines in renal function and increased sensitivity to CNS effects 6, 7.
- Patients with underlying CNS disease or renal insufficiency are also at increased risk of FQ-induced delirium 5, 7.
- The use of FQs in patients with known or suspected CNS disorders that predispose to seizures should be done with caution 7.