Fluoroquinolones in diarrhoeal illness
Why their role is now limited, and the risks you must know
What are fluoroquinolones?
Includes ciprofloxacin, levofloxacin, moxifloxacin. Modern evidence shows risks often outweigh benefits for diarrhoea; they are no longer routine first-line.
Current role in diarrhoea (restricted)
Consider only when no safer alternative is suitable, resistance patterns support use, and risk factors are low. Often azithromycin is preferred.
When fluoroquinolones should NOT be used
- Mild or improving diarrhoea
- Likely viral gastroenteritis
- Suspected STEC — risk of HUS
- Children/adolescents except specialist circumstances
- Pregnancy unless specialist-directed
Major safety warnings (boxed warnings)
Tendon injury and rupture
- Achilles tendon most common
- Higher risk with age >60, corticosteroids, kidney disease
Stop the drug and seek care if tendon pain or swelling occurs.
Peripheral neuropathy
Tingling, numbness, burning pain, weakness — may be irreversible and can begin rapidly.
Central nervous system effects
Dizziness, confusion, agitation, hallucinations; seizures rarely.
Aortic aneurysm and dissection
Associated with increased risk; caution with known aneurysm, connective tissue disorders, vascular disease.
Heart rhythm effects
QT prolongation risk rises with other QT-prolonging drugs and electrolyte disturbance.
C. diff risk
Fluoroquinolones have a high association with C. diff infection.
Key takeaway: Fluoroquinolones are no longer routine treatment for diarrhoea. Serious risks mean they should be reserved for exceptional circumstances.