Standard regimen for community-acquired septic shock in adults

In adults with community-acquired septic shock of unknown source, antibiotic choice depends on whether toxic shock is suspected and whether there is low suspicion of infection with Neisseria meningitidis.

For adults with community-acquired septic shock of unknown source, as a 4-drug regimen useLegg, 2023:

1gentamicin intravenously; see Gentamicin initial dose calculator for adults for initial dose. See Principles of aminoglycoside use for prescribing considerations and subsequent dosing 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 tobramycin tobramycin tobramycin

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flucloxacillin 2 g intravenously, 4-hourly. For dosage adjustment in adults with kidney impairment, see flucloxacillin intravenous dosage adjustment flucloxacillin flucloxacillin flucloxacillin

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vancomycin 25 mg/kg (actual body weight) rounded up to nearest 125 mg, up to 3 g intravenously, as a loading dose. See Calculated vancomycin loading dosage in critically ill adults for calculated weight-based loading doses. Subsequent doses are dependent on weight and kidney function; see Intermittent vancomycin dosing for critically ill adults vancomycin vancomycin vancomycin

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ceftriaxone 2 g intravenously, 12-hourly¹. ceftriaxone ceftriaxone ceftriaxone

If there is a low suspicion of infection with N. meningitidis, ceftriaxone may be discontinued – seek expert advice.

For adults in whom toxic shock syndrome is suspected², add to the above regimen:

clindamycin 600 mg intravenously, 8-hourly for a minimum of 72 hours and until organ function has significantly improved³ clindamycin clindamycin clindamycin

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intravenous immunoglobulin (IVIg) 2 g/kg intravenously, as a single dose as soon as possible but not later than 72 hours. It is reasonable to give the dose in divided doses if it is not possible to give a single dose. intravenous immunoglobulin (IVIg)

These empirical regimens are intended for initial therapy only (up to 48 hours). Modify therapy as soon as additional information is available (eg source of infection, results of Gram stain, culture and susceptibility testing). Evaluate the appropriateness of antimicrobial therapy daily, with consideration given to the patient’s clinical status and the principles of antimicrobial stewardship.

¹ Ceftriaxone is included to provide activity against N. meningitidis. Typical features of N. meningitidis infection include fever, meningitis symptoms and a nonblanching, purpuric rash; leg pain, cold extremities and abnormal skin colour may also occur. Increasingly, N. meningitidis infection has an atypical presentation – gastrointestinal symptoms may predominate, as well as other nonspecific features; purpuric rash and meningitis symptoms may be absent.Return

² In adults, signs of toxic shock syndrome include hypotension, kidney impairment, coagulopathy, hyperbilirubinaemia, adult respiratory distress syndrome, generalised rash or soft tissue necrosis. For more information, see Streptococcal toxic shock syndrome.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