Most Common Side Effects of Levofloxacin
The most common side effects of levofloxacin are gastrointestinal disturbances (nausea and bloating occurring in 0.5-1.8% of patients), neurologic effects (dizziness, insomnia, tremulousness, and headache occurring in 0.5% of patients), and cutaneous reactions (rash, pruritis, and photosensitivity occurring in 0.2-0.4% of patients). 1
Gastrointestinal Side Effects
- Nausea (0.5-1.8% of patients) 1
- Bloating (0.5-1.8% of patients) 1
- Vomiting (0.3-0.5% of patients) 2, 3
- Diarrhea (0.3-0.4% of patients) 2, 3
- Abdominal pain (0.4% of patients) 3
These gastrointestinal effects represent the highest frequency of adverse reactions among levofloxacin users, though the overall incidence remains relatively low compared to other antibiotics.
Neurological Side Effects
- Dizziness (0.3-0.5% of patients) 1, 3
- Insomnia (0.1-0.5% of patients) 1, 3
- Headache (0.1-0.5% of patients) 1, 3
- Tremulousness (0.5% of patients) 1
- Anxiety (0.1% of patients) 3
Neurological side effects are particularly important to monitor as they may impact quality of life and daily functioning. Patients with multiple sclerosis should be especially cautious with levofloxacin due to potential exacerbation of neurological symptoms 4.
Dermatological Side Effects
- Rash (0.2-0.5% of patients) 1, 3
- Pruritis (0.2-0.4% of patients) 1
- Photosensitivity (0.2-0.4% of patients) 1
Serious but Rare Side Effects
While not among the most common, several serious adverse effects warrant mention due to their potential impact on morbidity and mortality:
- Tendon inflammation and rupture (rare but significant) 1, 2
- QTc prolongation (rare; more common with electrolyte disturbances) 1, 2
- Peripheral neuropathy (potentially irreversible) 2
- Hypoglycemia (uncommon; primarily in patients on hypoglycemic medications) 1, 2
- Hepatotoxicity (rare) 2
- Clostridium difficile-associated diarrhea 2
Monitoring Recommendations
For patients on levofloxacin therapy:
- Monitor for gastrointestinal symptoms, which are most common
- Be vigilant for neurological symptoms, especially in patients with pre-existing CNS disorders
- Advise patients to avoid excessive sun exposure due to photosensitivity risk
- For long-term therapy, consider ECG monitoring at baseline and after 2 weeks 1
- Monitor blood glucose in diabetic patients 1
Important Precautions
- Avoid in pregnancy due to teratogenic potential 1
- Use with caution in patients over 60 years, those on corticosteroids, or with history of tendon disorders 1, 2
- Ensure adequate hydration to prevent crystalluria 2
- Avoid antacids or medications with divalent cations within 2 hours of levofloxacin administration 1
- Adjust dosage in patients with renal impairment (creatinine clearance <50 ml/min) 1
Recognizing these common side effects early can help improve patient adherence and prevent progression to more serious adverse reactions that could impact morbidity, mortality, and quality of life.