Fluoroquinolone Eyedrop Side Effects
Fluoroquinolone eyedrops are generally well-tolerated with minimal systemic toxicity, causing primarily mild ocular adverse events in approximately 1-6% of patients, including eye discomfort, irritation, and hyperemia. 1
Common Ocular Side Effects
The most frequently reported ocular adverse events with fluoroquinolone eyedrops include:
- Conjunctivitis (1-6% of patients) 1
- Ocular discomfort and pain (1-6% of patients) 1
- Ocular hyperemia (redness, 1-6% of patients) 1
- Ocular pruritus (itching, 1-6% of patients) 1
- Dry eye (1-6% of patients) 1
- Decreased visual acuity (1-6% of patients) 1
- Keratitis (1-6% of patients) 1
- Subconjunctival hemorrhage (1-6% of patients) 1
- Tearing (1-6% of patients) 1
Most ocular adverse events are mild in severity and self-limited. 2
Systemic Side Effects
Nonocular adverse events are uncommon but may include:
- Fever (1-4% of patients) 1
- Increased cough (1-4% of patients) 1
- Pharyngitis (1-4% of patients) 1
- Rhinitis (1-4% of patients) 1
- Rash (1-4% of patients) 1
- Otitis media (1-4% of patients) 1
Systemic toxicity of fluoroquinolones is not a concern with topical ophthalmic therapy, as the exposure is minimal compared to oral or intravenous administration. 3
Serious Adverse Reactions (Rare)
Hypersensitivity Reactions
- Serious and occasionally fatal anaphylactic reactions have been reported with systemically administered quinolones, though extremely rare with topical use 1
- Reactions may include cardiovascular collapse, loss of consciousness, angioedema (laryngeal, pharyngeal, or facial edema), airway obstruction, dyspnea, urticaria, and itching 1
- If an allergic reaction occurs, discontinue the drug immediately and provide emergency treatment as needed 1
Corneal Effects
- Corneal precipitation may occur, particularly with ciprofloxacin and to a lesser extent norfloxacin, but does not typically interfere with healing 4
- In approximately 10% of cases with corneal precipitation, delayed healing and corneal perforation may occur 5
- Corneal toxicity appears to be dose-dependent and results from class effects 5
Other Rare Toxicities
- Phototoxicity and neurotoxicity have been reported with fluoroquinolones 5
- Toxic effects on ocular collagen may be associated with Achilles tendinopathy, though this is primarily a concern with systemic administration 5
Safety Profile in Clinical Studies
- In a 7-day study of healthy adults using moxifloxacin 0.5% or levofloxacin 0.5% three times daily, no significant functional or morphological corneal changes were observed on examination including tear film breakup time, Schirmer test, or specular microscopy 6
- Repeated-dose studies in animals using concentrations up to 3% moxifloxacin showed no effects on cornea, corneal thickness, intraocular pressure, or corneal endothelium compared to controls 7
- Both moxifloxacin and besifloxacin were reported to be well tolerated in a study of 447 pediatric patients aged 1-17 years with bacterial conjunctivitis 3
Important Clinical Caveats
Prolonged Use Risks
- Prolonged use may result in overgrowth of non-susceptible organisms, including fungi 1
- If superinfection occurs, discontinue use and institute alternative therapy 1
Contact Lens Wear
- Patients should be advised not to wear contact lenses if they have signs or symptoms of bacterial conjunctivitis 1
Contraindications
- Fluoroquinolone eyedrops are contraindicated in patients with a history of hypersensitivity to moxifloxacin, other quinolones, or any components in the medication 1
Drug Interactions
- Moxifloxacin does not inhibit major cytochrome P450 enzymes (CYP3A4, CYP2D6, CYP2C9, CYP2C19, CYP1A2), making drug-drug interactions unlikely 1
Special Populations
Pregnancy
- No adequate studies exist in pregnant women 1
- Animal studies at high doses showed fetal toxicity only at maternally toxic doses (277-2864 times human exposure) 1
- The NOAEL (No-Observed-Adverse-Effect-Level) for developmental toxicity was 30-246 times the human ophthalmic dose in animal studies 1