Modification and duration of therapy for complicated diverticulitis

For patients with complicated diverticulitis, modify therapy based on the results of culture and susceptibility testing, if available.

If a gentamicin- or tobramycin-containing regimen was used and the results of susceptibility testing are not available 72 hours after the initial dose, switch to a non-aminoglycoside–containing regimen if intravenous therapy is still required.

Antifungal therapy may be required if yeast are identified in samples from deep surgical sites – seek expert advice and consult specialist guidelines (eg Consensus guidelines for the diagnosis and management of invasive candidiasis in haematology, oncology and intensive care settings).

Switch to oral therapy once the patient is improving, haemodynamically stable and able to tolerate oral medication – see Guidance for antimicrobial intravenous to oral switch. If results of susceptibility testing are not available, for oral continuation therapy:

• in patients without penicillin hypersensitivity, use amoxicillin+clavulanate.
• in patients with nonsevere (immediate or delayed) penicillin hypersensitivity, or severe immediate¹ penicillin hypersensitivity who tolerated ceftriaxone, use cefuroxime plus metronidazole.
• in patients with severe immediate¹ penicillin hypersensitivity in whom ceftriaxone was not used nor tolerated, or for patients with severe delayed² penicillin hypersensitivity, use trimethoprim+sulfamethoxazole plus metronidazole.

The total duration of therapy (intravenous + oral) is:

• patients who have not undergone surgery – 7 to 10 days
• patients who have undergone surgery – 4 days after adequate surgical source control has been achievedSawyer, 2015.