What oral antibiotic regimen is recommended for a patient with a penicillin allergy, being discharged after receiving intravenous (IV) ceftriaxone (Rocephin) and metronidazole (Flagyl) for diverticulitis management?

From the Guidelines

For patients with penicillin allergy who are being discharged after inpatient treatment of diverticulitis with ceftriaxone and metronidazole, I recommend an oral antibiotic regimen of moxifloxacin 400 mg once daily for 7-10 days, as it provides broad-spectrum coverage against the typical polymicrobial flora involved in diverticulitis, including gram-negative organisms and anaerobes, without the need for combination therapy 1. When selecting an oral antibiotic for discharge, it is crucial to consider the patient's allergy history, the severity of the infection, and the potential for antimicrobial resistance. Given the patient's penicillin allergy, moxifloxacin is a suitable option as it is a fluoroquinolone with activity against a wide range of gram-positive and gram-negative organisms, including those commonly involved in diverticulitis 1. Some key points to consider when prescribing moxifloxacin include:

• Ensuring the patient has not received quinolone therapy within the past 3 months to minimize the risk of quinolone-resistant organisms 1
• Assessing the patient's renal function, as moxifloxacin is contraindicated in patients with severe renal impairment
• Counseling the patient on potential side effects, including gastrointestinal upset, dizziness, and photosensitivity
• Emphasizing the importance of completing the full course of antibiotics to minimize the risk of treatment failure and antimicrobial resistance It is also essential to note that while combination therapy with metronidazole may be considered in some cases, moxifloxacin's broad-spectrum activity makes it a suitable monotherapy option for patients with penicillin allergy 1.

From the FDA Drug Label

Clinical success rates in evaluable patients were 89% (108/122) for moxifloxacin hydrochloride and 91% (110/121) for cephalexin hydrochloride. The overall clinical success rates in the clinically evaluable patients are shown in Table 18 Table 18: Clinical Success Rates in Patients with Complicated Intra-Abdominal Infections Study Moxifloxacin Hydrochloride n/N (%) Comparator n/N (%) 95% Confidence Interval North America (overall) 146/183 (79.8%) 153/196 (78.1%)(-7.4%, 9.3%) International (overall) 199/246 (80.9%) 218/265 (82.3%)(-8.9%, 4. 2%)

Moxifloxacin can be considered as an oral antibiotic for the management of diverticulitis in patients with a penicillin allergy, especially when they have received ceftriaxone and metronidazole as inpatients.

• The clinical success rates of moxifloxacin hydrochloride in treating complicated intra-abdominal infections, which include conditions like diverticulitis, are around 79.8% to 80.9%.
• Moxifloxacin has been shown to be effective in treating various infections, including those caused by bacteria that may be involved in diverticulitis.
• However, it is essential to note that the specific use of moxifloxacin for diverticulitis is not explicitly mentioned in the provided drug label, but its efficacy in complicated intra-abdominal infections makes it a potential option 2.

From the Research

Oral Antibiotic Options for Diverticulitis Management

Given the patient's penicillin allergy and inpatient treatment with ceftriaxone and metronidazole, the following oral antibiotic options can be considered for discharge:

• Metronidazole and a fluoroquinolone (such as ciprofloxacin or levofloxacin) 3
• Alternatively, amoxicillin-clavulanate can be considered, but given the patient's penicillin allergy, this may not be suitable
• Piperacillin/tazobactam is another option, but it is typically administered intravenously, and oral formulations may not be available 4

Considerations for Antibiotic Selection

When selecting an oral antibiotic for diverticulitis management, consider the following:

• The patient's allergy history, including penicillin allergy
• The severity of the diverticulitis and the need for broad-spectrum coverage
• The potential for antibiotic resistance and the risk of Clostridioides difficile infection
• The patient's renal function and potential interactions with other medications

Duration of Antibiotic Therapy

The optimal duration of antibiotic therapy for diverticulitis is not well established, but typical treatment courses range from 7 to 14 days 5. The decision to extend or shorten antibiotic therapy should be based on the patient's clinical response and the presence of any complications.