What are the proper antibiotics for perforated appendicitis?

From the Guidelines

For perforated appendicitis, the recommended antibiotic regimen is piperacillin-tazobactam 3.375g IV every 6 hours, or alternatively, a combination of ceftriaxone 1-2g IV daily plus metronidazole 500mg IV every 8 hours, as these regimens provide broad-spectrum coverage against both aerobic and anaerobic bacteria, including E. coli and Bacteroides fragilis, which are commonly found in appendicitis. The choice of antibiotics should be based on local microbiologic data, cost advantage, allergies, and formulary availability 1. For patients with penicillin allergies, ciprofloxacin 400mg IV every 12 hours plus metronidazole 500mg IV every 8 hours is an appropriate alternative 1. These antibiotics should be started immediately after diagnosis and continued for 5-7 days, depending on clinical response, with the duration extended if there are complications such as abscess formation 1. Following surgical intervention (appendectomy), antibiotics are continued to prevent further infection spread, with the recommendation to not prolong antibiotics longer than 3-5 days postoperatively in case of complicated appendicitis with adequate source control 1. Adequate fluid resuscitation and pain management should accompany antibiotic therapy, and patients should be monitored for signs of improvement or deterioration. The use of a single dose of broad-spectrum antibiotics given preoperatively has been shown to be effective in decreasing wound infection and postoperative intra-abdominal abscess, regardless of the degree of inflammation of the removed appendix 1. In patients with complicated acute appendicitis, postoperative broad-spectrum antibiotics are suggested, especially if complete source control has not been achieved, with discontinuation of antibiotics after 24 hours seeming safe and associated with shorter length of hospital stay and lower costs 1. The optimal course of antibiotics remains to be identified, but current evidence suggests that longer postoperative courses do not prevent surgical site infections compared to shorter courses 1. It is essential to consider the potential for antimicrobial resistance and to use antibiotics judiciously, with the selection of antibiotics based on local epidemiology and susceptibility patterns 1. In cases where the patient has a history of antibiotic exposure or is at risk for infection with resistant organisms, broader-spectrum coverage may be necessary, with the use of agents such as ertapenem or tigecycline considered 1. However, the use of these agents should be balanced against the potential risks of promoting further resistance and the increased cost 1. Ultimately, the choice of antibiotic regimen should be individualized based on the patient's specific needs and the local epidemiology of antimicrobial resistance.

From the FDA Drug Label

Piperacillin and tazobactam for injection, USP is indicated in adults and pediatric patients (2 months of age and older) for the treatment of appendicitis (complicated by rupture or abscess) and peritonitis caused by beta-lactamase producing isolates of Escherichia coli or the following members of the Bacteroides fragilis group: B. fragilis, B. ovatus, B. thetaiotaomicron, or B. vulgatus. The proper antibiotic for perforated appendicitis is Piperacillin/Tazobactam (IV), as it is indicated for the treatment of appendicitis complicated by rupture or abscess 2.

From the Research

Proper Antibiotics for Perforated Appendicitis

• The use of broad-spectrum antibiotics is warranted in the treatment of perforated appendicitis 3, 4, 5, 6.
• Studies have shown that antibiotics such as piperacillin-tazobactam, ceftriaxone, and metronidazole can be effective in treating perforated appendicitis 7, 3, 5, 6.
• A 2-drug regimen of ceftriaxone and Flagyl (metronidazole) with once-a-day dosing has been shown to be a simple and cost-effective antibiotic regimen for perforated appendicitis 5.
• Reducing the use of piperacillin and tazobactam for pediatric perforated appendicitis has been shown to be safe and effective, with no significant difference in clinical outcomes 6.
• The use of postoperative antibiotics is only recommended in cases of perforation, and treatment should be given intravenously for a minimum period of 3-5 days for adult patients, until clinical signs such as fever resolve and laboratory parameters such as C-reactive protein curve and white blood cell (WBC) start to decline 4.

Antibiotic Regimens

• Broad-spectrum antibiotics such as piperacillin-tazobactam monotherapy or combination therapy with either cephalosporins or fluroquinolones with metronidazole can be used to treat uncomplicated acute appendicitis 7.
• A 2-drug regimen of ceftriaxone and metronidazole can be used as an alternative to traditional triple antibiotic coverage for pediatric perforated appendicitis 5.
• Ceftriaxone and metronidazole can be used as a default regimen for pediatric perforated appendicitis, with a significant reduction in piperacillin and tazobactam use 6.

Clinical Outcomes

• The use of broad-spectrum antibiotics has been shown to have no beneficial clinical effects in patients with perforated appendicitis who underwent surgical intervention 3.
• The use of a 2-drug regimen of ceftriaxone and Flagyl (metronidazole) has been shown to allow patients to more rapidly defervesce compared to traditional triple antibiotic coverage 5.
• Reducing the use of piperacillin and tazobactam for pediatric perforated appendicitis has been shown to have no significant difference in clinical outcomes, including mean duration of antibiotic therapy, mean length of stay, rate of surgical site infection, and rate of 30-day readmission and emergency department visit 6.