Treatment Guideline Chart
Diverticulitis is the inflammation of the diverticulum which is a herniation of the mucosa and submucosa of the colonic wall that may fill with fecal material or undigested food particles. 
Abdominal pain is usually localized, abrupt, steady and may worsen over time.
Other signs and symptoms are fever, anorexia, nausea without vomiting, and altered bowel movements, commonly constipation but may also present with diarrhea or tenesmus.

Diverticulitis Treatment

Principles of Therapy

  • Reserved for patients with complicated diverticulitis 
    • Small abscesses (<3 cm) are usually responsive to antibiotic treatment alone
  • Antibiotics to be used should cover the usual pathogens in local infection:
    • Anaerobes eg Bacteroides fragilis, Clostridium sp, Peptostreptococcus sp, Prevotella spp
    • Aerobic organisms eg E coli, Klebsiella sp, Proteus sp, Enterobacteriaceae, enterococci, Streptococcus sp
    • If an abscess is present, coverage for Pseudomonas aeruginosa should be given
  • Local resistance patterns should be taken into consideration
  • Other factors affecting the choice of antibiotics:
    • History of antibiotic allergy
    • Previous response to antibiotics
    • Recent antibiotic use


Outpatient Antibiotic Therapy

  • Oral broad-spectrum antibiotic therapy should be given for 7-10 days or up to 14 days depending on patient’s response
  • Antibiotics that may be used include:
    • Combination of Ciprofloxacin (or Levofloxacin) plus Metronidazole is frequently used
    • Amoxicillin/clavulanic acid, Ampicillin/sulbactam or Co-trimoxazole
    • Clindamycin or Moxifloxacin may be given to patients intolerant to Metronidazole

Inpatient Antibiotic Therapy

  • Empiric broad-spectrum IV antibiotics should be administered to hospitalized patients (eg septic and immunocompromised) pending culture results with therapy adjusted once results are available
    • IV antibiotic therapy is given for 3-5 days, then patient is transitioned to oral antibiotics to complete a 10- to 14-day course

Monotherapy that may be used includes the following: 

  • Coverage with a single antibiotic that has activity against potential pathogens has been shown to be as effective as combination therapy
  • Beta-lactam/beta-lactamase combinations (eg aminopenicillins/beta-lactamase inhibitors, Piperacillin/tazobactam or Ticarcillin/clavulanic acid)
  • Carbapenems are used for severe cases (eg Imipenem, Meropenem)
    • Ertapenem may be used for mild-moderate disease
  • Cephalosporins (2nd generation) with both aerobic/anaerobic Gram-negative coverage
    • Eg Cefoxitin, Cefotetan
    • These agents should be used with caution because B fragilis microorganisms have been increasingly found to be resistant to these agents

Combination therapy that may be used includes the following:

  • Ampicillin plus Gentamicin plus Metronidazole
  • Ciprofloxacin (or Levofloxacin) plus Metronidazole, with or without Ampicillin
  • Piperacillin/tazobactam or Imipenem/cilastatin plus Metronidazole
  • Metronidazole or Clindamycin plus (3rd generation cephalosporin or aminoglycoside)
  • Severe penicillin/cephalosporin allergy: Aztreonam or Ciprofloxacin plus Metronidazole plus Vancomycin

Other Antibiotic

  • Rifaximin plus fiber may provide relief in patients with uncomplicated symptomatic diverticular disease; however, it does not prevent recurrent diverticulitis

Pain Management

  • May use Paracetamol for simple analgesia
  • Meperidine is an appropriate choice if the patient requires narcotics for analgesia
  • Avoid Morphine sulfate because it may cause colonic spasm


Optimal fluid and electrolyte status should be maintained

Patients with Mild Disease (Outpatient)

  • A liquid diet may be given with the diet advanced once symptoms improve

Patients with Moderate to Severe Disease (Inpatient)

  • May be given clear liquid diet or be NPO (bowel rest) depending on symptom severity
  • Administer intravenous (IV) fluids
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