Penicillin hypersensitivity regimens for complicated diverticulitis

For empirical therapy of complicated diverticulitis in adults without sepsis or septic shock who have had a nonsevere (immediate or delayed) hypersensitivity reaction to a penicillin, use:

ceftriaxone 2 g intravenously, daily. See advice on modification and duration of therapy ceftriaxone ceftriaxone ceftriaxone

PLUS

metronidazole 500 mg intravenously, 12-hourly. See advice on modification and duration of therapy. metronidazole metronidazole metronidazole

For patients who have had a severe immediate¹ hypersensitivity reaction to a penicillin, the regimen above can be considered if a beta-lactam antibiotic is strongly preferred (for considerations, see Severe immediate hypersensitivity: Implications of cross-reactivity between penicillins and cephalosporins).

For patients who have had a severe immediate¹ hypersensitivity reaction to a penicillin in whom the regimen above is not used, or for patients who have had a severe delayed² hypersensitivity reaction to a penicillin, as a 2-drug regimen, use:

1gentamicin intravenously; see Gentamicin initial dose calculator for adults for initial dose. See Principles of aminoglycoside use for prescribing considerations and subsequent dosing. See advice on modification and duration of therapy gentamicin gentamicin gentamicin

1tobramycin intravenously; see Tobramycin initial dose calculator for adults for initial dose. See Principles of aminoglycoside use for prescribing considerations and subsequent dosing. See advice on modification and duration of therapy tobramycin tobramycin tobramycin

PLUS with either of the above drugs

clindamycin 600 mg intravenously, 8-hourly³. See advice on modification and duration of therapy. clindamycin clindamycin clindamycin

If the clindamycin-containing regimen is used and prompt source control (eg percutaneous drainage, peritoneal lavage, colonic resection) is unlikely to occur (eg within 24 hours), consider adding metronidazole because there is increasing resistance to clindamycin in gram-negative anaerobes (especially Bacteroides species); add:

metronidazole 500 mg (child: 12.5 mg/kg up to 500 mg) intravenously, 12-hourly. See advice on modification and duration of therapy. metronidazole metronidazole metronidazole

¹ Severe immediate hypersensitivity reactions include anaphylaxis, compromised airway, airway angioedema, hypotension and collapse.Return

² Severe delayed hypersensitivity reactions include cutaneous adverse drug reactions (eg drug rash with eosinophilia and systemic symptoms [DRESS], Stevens–Johnson syndrome/toxic epidermal necrolysis [SJS/TEN], severe blistering or desquamative rash), and significant internal organ involvement (eg acute interstitial nephritis).Return

³ There are more clinical and microbiological data to support the use of clindamycin than lincomycin. Intravenous lincomycin can be used at the same dosage if clindamycin is unavailable or if a local protocol recommends its use.Return