UMEM Educational Pearls

Category: Neurology

Title: Neurological Adverse Reactions with Antimicrobials

Keywords: drug reaction, toxicity, neurotoxicity, antibiotics (PubMed Search)

Posted: 11/10/2021 by WanTsu Wendy Chang, MD (Emailed: 11/11/2021)
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  • Antimicrobial medications can be associated with neurological adverse reactions. 
  • An individual’s risk is influenced by their age, weight, nutritional status, the medications they are taking concurrently, and pharmacological properties (dosage, half-life, CNS permeability). 
  • Encephalopathy 
    • Seen with beta-lactams, fluoroquinolones, clarithromycin, and sulfamethoxazole-trimethoprim. 
    • Most commonly with cefepime. 
    • Higher risk in elderly, renal dysfunction, and preexisting CNS disease. 
  • Seizures 
    • Beta-lactams block GABA receptors. 
    • Highest risk with cefepime and imipenem. 
  • Peripheral neuropathy 
    • Associated with metronidazole, fluoroquinolones, linezolid, chloramphenicol, and isoniazid. 
    • Most cases are dose dependent. 
    • Some cases are irreversible. 
  • Ototoxicity 
    • Aminoglycosides cause cochlear NMDA receptor excitotoxicity. 
  • Weakness 
    • Fluoroquinolones, macrolides, and aminoglycosides inhibit acetylcholine release and bind neuromuscular junction receptors. 
    • Should be avoided in myasthenia gravis and Lambert-Eaton syndrome. 
  • Movement disorders 
    • Tremors – sulfamethoxazole-trimethoprim 
    • Dyskinesia, dystonic reactions – fluoroquinolones, chloramphenicol 
    • Cerebellar syndrome – metronidazole, aminoglycosides 

Bottom Line: Recognition of antibiotic associated neurotoxicity reduces unnecessary workup and serious adverse effects. 


  • Vo ML. Commonly used drugs for medical illness and the nervous system. Continuum (Minneap Minn) 2020;26(3, Neurology of Systemic Disease):716-731. 

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