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ANTIINFECTIVES FOR SYSTEMIC USE › ANTIBACTERIALS FOR SYSTEMIC USE › COMBINATIONS OF ANTIBACTERIALS › Combinations of antibacterials
norfloxacin and metronidazole
J01RA14
Forms & Strengths
- Tablet: Norfloxacin 400 mg + Metronidazole 500 mg
Adult Dosing
- Infectious diarrhea / dysentery: 1 tablet orally twice daily for 5 to 7 days
Pediatric Dosing
- Not recommended for pediatric patients due to the risk of fluoroquinolone-associated arthropathy and cartilage damage
Indications
- Treatment of mixed bacterial gastrointestinal infections and infectious diarrhea caused by susceptible aerobic and anaerobic organisms
Mechanism of Action
- Norfloxacin inhibits bacterial DNA synthesis through inhibition of bacterial DNA gyrase and topoisomerase IV
- Metronidazole is reduced by anaerobic bacterial proteins, forming reactive nitro radicals that damage microbial DNA
Contraindications
- Hypersensitivity to norfloxacin, metronidazole, other quinolones, or nitroimidazole derivatives
- History of quinolone-associated tendinitis or tendon rupture
- Concomitant administration with tizanidine
- Pregnancy (first trimester) and lactation for metronidazole component
- Pre-existing CNS disorders or blood dyscrasias
Adverse Reactions
- Nausea
- Diarrhea
- Abdominal pain
- Metallic taste
- Headache
- Dizziness
- Tendinitis and tendon rupture
- QT prolongation
- Peripheral neuropathy
- Clostridium difficile-associated diarrhea
Drug Interactions
- Disulfiram-like reaction with concurrent alcohol intake
- Potentiation of oral anticoagulants (e.g., warfarin), increasing bleeding risk
- Increased serum levels of theophylline, cyclosporine, and tacrolimus
- Decreased absorption when co-administered with multivalent cations (antacids, iron, sucralfate)
- Increased risk of QT prolongation with class IA and III antiarrhythmics
Curated Content: Needs Vetting Before Put to Clinical Use