Oral Antibiotic Regimen for Infectious Terminal Ileitis
For a patient with infectious terminal ileitis who is clinically improving and tolerating oral intake, transition to oral ciprofloxacin 500-750 mg twice daily plus metronidazole 500 mg three times daily to complete a 10-14 day total course. 1
Rationale for Oral Transition
When patients with intra-abdominal infections (including terminal ileitis) can tolerate oral intake and are clinically improving, oral antimicrobial therapy is as effective as continued intravenous therapy. 1 In a prospective blinded study of 330 patients with complicated intra-abdominal infections, 47% were successfully switched to oral therapy with only a 4% treatment failure rate, compared to 23% failure in those not switched—demonstrating that oral therapy is not only safe but potentially superior when patients can tolerate it. 1
Specific Oral Regimen
- Ciprofloxacin: 500-750 mg orally twice daily 1
- Metronidazole: 500 mg orally three times daily 1
- Duration: Complete a total of 10-14 days of therapy (combining IV and oral days) 1
The combination provides:
- Excellent gram-negative aerobic coverage (ciprofloxacin) 1
- Anaerobic coverage (metronidazole) 1, 2
- High bioavailability (≥90% absorption) achieving serum/tissue concentrations comparable to IV administration 3
Timing of Transition
Switch to oral therapy when the patient meets these criteria:
- Tolerating oral intake 1
- Clinically improving (defervescence, reduced abdominal pain) 1, 3
- Typically between 3-8 days after starting IV therapy 1
- No signs of shock or impaired intestinal absorption 3
Important Caveats
Do not use this regimen if the patient has:
- Ileus or inability to tolerate oral intake 3
- Hemodynamic instability or shock 3
- Signs of fulminant disease (perforation, toxic megacolon) 4
Avoid antiperistaltic agents and opiates as they worsen outcomes in infectious enterocolitis by promoting toxin retention. 4
Alternative Considerations
If the terminal ileitis is due to Butyricimonas species (rare anaerobic pathogen), the same regimen of ceftriaxone or ciprofloxacin plus metronidazole is appropriate, though most cases respond to conservative short-course antimicrobial therapy. 2 However, drug resistance has been reported in some Butyricimonas cases, so clinical monitoring is essential. 2
For non-specific isolated terminal ileal abnormalities (NSITIA), antimicrobial therapy including rifaximin, albendazole, and tinidazole showed no benefit over symptomatic treatment, with 88-92% spontaneous resolution in both groups. 5 This suggests that if the patient is improving, the infectious etiology is likely responding to current therapy rather than representing NSITIA.
Monitoring
Continue oral therapy until completion of the 10-14 day course, monitoring for: