What antibiotics can cause myoclonus and jerking movements?

Fluoroquinolones Are the Primary Antibiotics That Cause Myoclonus and Jerking Movements

Fluoroquinolone antibiotics are the most well-documented class of antibiotics associated with myoclonus and jerking movements, with ciprofloxacin having the strongest evidence for causing these neurological adverse effects. 1

Fluoroquinolones and Neurological Effects

• Fluoroquinolones can cause a variety of muscle syndromes ranging from mild myalgias to severe manifestations including myoclonus and jerking movements 2
• These neurological adverse effects typically manifest within one week after starting fluoroquinolone treatment 2
• Symptoms often resolve within 1-4 weeks after discontinuation of the medication, though some cases have persisted for up to 6 months 2
• The fluorine atom in fluoroquinolones is thought to be a key trigger for these muscle disorders 2

Specific Fluoroquinolones Associated with Myoclonus

• Ciprofloxacin has level A evidence (highest level) for causing myoclonus according to systematic reviews 1
• Levofloxacin has been specifically documented to cause reversible myoclonus/chorea in case reports 3
• Ofloxacin and norfloxacin have been associated with muscle disorders including myoclonus 2

Pathophysiological Mechanisms

• The etiology of fluoroquinolone-associated muscle disorders appears to be related to:
  1. Possible latent myopathic disorders that are revealed by fluoroquinolone exposure 2
  2. Metabolic abnormalities in muscle tissue that can be detected through specialized testing 2
  3. Interaction with neurotransmitter systems including serotonin, dopamine, GABA, and glutamate 1

Risk Factors for Developing Myoclonus with Fluoroquinolones

• Pre-existing muscular anomalies or myopathic processes 2, 4
• Concurrent use of statins significantly increases the risk of muscle-related adverse effects 2, 4
• Renal disease or impairment 4
• Advanced age 4
• History of malignant hyperthermia susceptibility 2

Clinical Presentation

• Symptoms typically consist of diffuse muscle pain with or without weakness 2
• There may be a predilection for proximal muscle groups 2
• Jerking movements can range from mild to severe and disabling 5
• Myoclonus presents as quick, simple jerks, while chorea combines with other, slower movements in a continuous, flowing fashion 6

Management Recommendations

• Immediately discontinue the fluoroquinolone if myoclonus or other muscle symptoms develop 2, 4
• Protect the affected area to limit further injury 2
• For treatment of established myoclonus:
  • Levetiracetam, valproic acid, and clonazepam are first-line agents for cortical myoclonus 7
  • Clonazepam is the first-line agent for subcortical, brainstem, and spinal myoclonus 7
  • Avoid phenytoin and carbamazepine as they may paradoxically worsen myoclonus 7

Prevention Strategies

• Use alternative antibiotics in patients with risk factors when possible 4
• Avoid concomitant corticosteroid administration with fluoroquinolones 2, 4
• Limit high-intensity physical activity during fluoroquinolone treatment 2
• Consider magnesium supplementation during treatment (administered at different times than the fluoroquinolone to avoid decreased antibiotic efficacy) 4

Important Caveats

• The onset of myoclonus can be rapid and may occur even in patients without prior neurological disorders 3
• Myoclonus may persist for weeks to months after discontinuation of the fluoroquinolone 2
• Patients taking both fluoroquinolones and statins should be monitored particularly closely for muscle-related adverse effects 2, 4
• There are no FDA-approved medications specifically for drug-induced myoclonus, and most therapies are borrowed from antiepileptic and psychiatric treatments 5