What are the potential drug interactions with Oflox (Ofloxacin)?

Potential Drug Interactions with Ofloxacin (Oflox)

Ofloxacin has several important drug interactions that can affect its efficacy and safety profile. The most significant interactions include antacids containing divalent cations, certain medications that prolong QT interval, and NSAIDs. 1

Major Drug Interactions

Absorption Interactions

• Antacids containing aluminum, magnesium, or other divalent/trivalent cations:
  • Significantly reduce ofloxacin absorption
  • Administer ofloxacin at least 2 hours before or after these medications 1
  • Also applies to iron supplements, zinc products, and multivitamins containing these minerals

Cardiovascular Interactions

• QT-prolonging medications:
  • Avoid combining with Class IA (quinidine, procainamide) or Class III (amiodarone, sotalol) antiarrhythmics
  • Increased risk of torsade de pointes and other arrhythmias 1
  • Monitor ECG if combination cannot be avoided

Central Nervous System Interactions

• NSAIDs (particularly fenbufen):

  • Increased risk of CNS stimulation and seizures 2
  • Pharmacodynamic interaction involving GABA inhibition
  • Particularly important in elderly patients or those with seizure disorders

• Theophylline:

  • Unlike some other fluoroquinolones (ciprofloxacin, enoxacin), ofloxacin does not significantly inhibit theophylline metabolism 2, 3
  • However, may have pharmacodynamic interaction increasing seizure risk

Metabolic Interactions

• Hypoglycemic agents:
  • May potentiate action of oral hypoglycemic drugs (e.g., glyburide) or insulin
  • Risk of severe hypoglycemia, sometimes resulting in coma 1
  • Monitor blood glucose closely if combination necessary

Special Population Considerations

Renal Impairment

• Ofloxacin is primarily eliminated through renal excretion (80% recovered in urine within 24 hours) 4
• Dosage adjustment required for patients with creatinine clearance ≤50 mL/min 1
• Increased risk of adverse effects due to drug accumulation

Hepatic Impairment

• Although ofloxacin is not extensively metabolized by the liver 2, careful monitoring is recommended in patients with hepatic insufficiency 1

Elderly Patients

• More susceptible to QT interval prolongation
• May have reduced renal function requiring dose adjustment
• Higher risk of CNS effects including confusion, dizziness, and seizures 1

Other Important Considerations

Photosensitivity

• Moderate to severe photosensitivity/phototoxicity reactions can occur
• Avoid excessive exposure to sunlight or UV light during treatment 1
• Reactions may manifest as exaggerated sunburn (burning, erythema, vesicles, blistering)

Musculoskeletal Effects

• Risk of tendinitis and tendon rupture, especially in:
  • Patients over 60 years
  • Those taking corticosteroids
  • Patients with kidney, heart, or lung transplants 1, 5
• Discontinue at first sign of tendon pain or inflammation

Comparison with Other Fluoroquinolones

Ofloxacin has fewer drug interactions compared to some other fluoroquinolones:

• Unlike ciprofloxacin and enoxacin, ofloxacin does not significantly inhibit cytochrome P450 enzymes 2, 3
• Less likely to interact with drugs metabolized by the liver (e.g., theophylline, warfarin, cyclosporine) 3
• This makes ofloxacin potentially safer in patients taking multiple medications

Monitoring Recommendations

1. Baseline assessment of renal and hepatic function
2. ECG monitoring if combined with other QT-prolonging drugs
3. Blood glucose monitoring if used with hypoglycemic agents
4. Vigilance for signs of tendon pain or CNS effects
5. Patient education about photosensitivity and avoiding UV exposure

Ofloxacin's relatively favorable drug interaction profile compared to other fluoroquinolones makes it a valuable option when drug interactions are a concern, though careful monitoring is still required, particularly in high-risk populations.