From the Guidelines
Antibiotics are not necessary for the treatment of uncomplicated perirectal abscesses, but may be indicated in patients with systemic symptoms, immunocompromised status, or extensive cellulitis, and should cover skin flora and anaerobes. When antibiotics are needed, the choice of regimen should be based on the most recent and highest quality evidence. According to the 2021 WSES-AAST guidelines 1, antibiotics may be considered in patients with anorectal abscess who have sepsis, surrounding soft tissue infection, or disturbances of the immune response. Some key points to consider when deciding on antibiotic therapy for perirectal abscesses include:
- The primary treatment is surgical incision and drainage, and antibiotics are typically not required unless there are specific risk factors present 1.
- Patients with systemic symptoms, immunocompromised status, extensive cellulitis, or other high-risk conditions may benefit from antibiotic therapy 1.
- The choice of antibiotic regimen should cover skin flora and anaerobes, and options may include amoxicillin-clavulanate, trimethoprim-sulfamethoxazole plus metronidazole, or clindamycin 1.
- The duration of antibiotic therapy is typically 5-10 days, but the evidence for this is low and more research is needed to determine the optimal duration 1.
- Sampling of drained pus may be considered in high-risk patients, such as those with risk factors for multidrug-resistant organism (MDRO) infection, recurrent infections, or non-healing wounds 1. An appropriate empiric regimen would be amoxicillin-clavulanate 875/125 mg orally twice daily for 5-7 days, as it provides broad-spectrum coverage of Gram-positive, Gram-negative, and anaerobic bacteria 1. Alternative options may include trimethoprim-sulfamethoxazole (one double-strength tablet twice daily) plus metronidazole (500 mg three times daily) for patients with penicillin allergy, or clindamycin (300-450 mg four times daily) for 5-7 days. Following drainage, patients should be instructed to take sitz baths 2-3 times daily, maintain good perianal hygiene, and follow up if symptoms worsen or do not improve within 48-72 hours after drainage.
From the FDA Drug Label
Ticarcillin Sodium / Potassium Clavulanate (30:1) The FDA drug label does not answer the question.
From the Research
Antibiotics for Perirectal Abscess Treatment
The following antibiotics are used to treat perirectal abscesses:
- Ciprofloxacin and metronidazole, as mentioned in the study 2
- Antibiotics covering typical gram-positive, gram-negative, and anaerobic organisms, as suggested in the study 3
Rationale for Antibiotic Use
The use of antibiotics in treating perirectal abscesses is supported by the following evidence:
- A study found that inadequate antibiotic coverage after incision and drainage of complicated peri-rectal abscess resulted in a six-fold increase in the re-admission rate 3
- Another study suggested that antibiotics appeared to be useful only as adjunct therapy in the treatment of perirectal abscesses 4
- The presence of MRSA in perirectal abscesses is underrecognized, and antibiotics may be necessary to provide adequate coverage 5
- A systematic review and meta-analysis found that antibiotic therapy following incision and drainage of anorectal abscesses is associated with a 36% lower odds of fistula formation 6
Key Findings
Key findings from the studies include:
- The prevalence of MRSA in perirectal abscesses is significant, with one study finding a prevalence of 19% 5
- The use of antibiotics may reduce the risk of fistula formation after incision and drainage of anorectal abscesses 6
- A multicentre, double-blind, randomised, placebo-controlled trial is currently investigating the effectiveness of adding antibiotic treatment to surgical drainage of perianal abscess 2