EXPLODING BACTERIAMed Decision Speed Tools
monobactamsUnverified

Aztreonam

Generic, Azactam®, Cayston® (inhaled)
?Pregnancy?Breastfeeding?Warfarin
Open the full CAP page →
Inpatient WITH Pseudomonas Risk Factors ± ICU
Consider antipseudomonal coverage if: prior Pseudomonas isolation from the respiratory tract, recent hospitalization with IV antibiotics (within 90 days), or structural lung disease (bronchiectasis, cystic fibrosis, advanced COPD).
ICU withOUT Pseudomonas Risk Factors
Aztreonam○Pick onerequired
+
Fluoroquinolone○Pick onerequired
+
Aminoglycoside○Pick onerequired
±
Anti-MRSA○Optionalif risk
Select
Aztreonam
???
Do NOT give aztreonam to those with a Ceftazidime₃ allergy (shared side chain → cross-reactivity).
2 g IV q8h
IV / IM
1 g vial2 g vial
Inhaled (Cayston®)
75 mg
BrandsGeneric, Azactam®, Cayston® (inhaled)
View full Aztreonam page →
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AND Select
Levofloxacin
???
750 mg IV/PO q24h
Liquid
25 mg/mL oral solution
Tablets
250 mg500 mg750 mg
IV
5 mg/mL (premix)25 mg/mL (vial)
BrandsGeneric, Levaquin®
View full Levofloxacin page →
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AND Choose ONE Aminoglycoside
Amikacin
???
Requires drug level monitoring.
15–20 mg/kg IV q24h
IV / IM
250 mg/mL50 mg/mL
BrandsGeneric, Amikin®
View full Amikacin page →
Gentamicin
???
Requires drug level monitoring.
5–7 mg/kg IV q24h
IV / IM
10 mg/mL40 mg/mL
BrandsGeneric, Garamycin®
View full Gentamicin page →
Tobramycin
???
Requires drug level monitoring.
5–7 mg/kg IV q24h
IV / IM
10 mg/mL40 mg/mL
Inhaled (Tobi®)
300 mg/5 mL
BrandsGeneric, Tobi® (inhaled)
View full Tobramycin page →
±
Consider ONE Anti-MRSAONLY if risk factors
Add anti-MRSA only for a real risk factor — it is not routine in CAP.
Risks: prior MRSA (infection, colonization, or positive nasal PCR); hospitalization or IV antibiotics ≤90 days; severe, necrotizing, or cavitary pneumonia; empyema; recent influenza; ESRD/dialysis; injection drug use.
Negative nasal PCR (NPV ~95–99%) → reasonable to withhold or stop.
VancomycinMRSA
???
Monitor: target AUC/MIC 400–600; check a level before the 4th dose.
15–20 mg/kg IV q8–12h
IV
500 mg750 mg1 g1.25 g5 g
Capsules — PO, C. diff only
125 mg250 mg
BrandsGeneric, Vancocin®
View full Vancomycin page →
LinezolidMRSA · VRE
???
600 mg IV/PO q12h
Tablets
600 mg
Liquid
100 mg/5 mL
IV
600 mg/300 mL
BrandsGeneric, Zyvox®
View full Linezolid page →
Other regimens for this scenario don't include Aztreonam — see the full page for the complete algorithm.
Open the full DFI page →
Scope: soft-tissue infection without evidence of osteomyelitis. Probe-to-bone or exposed bone suggests osteomyelitis — treat as osteomyelitis (different workup and a longer course).
Group A○Pick onerequired
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Anti-MRSA○Pick onerequired
Group A
Ampicillin-Sulbactam
???
3 g IV q6h
IV / IM
1.5 g (1 g / 0.5 g) vial3 g (2 g / 1 g) vial
BrandsGeneric, Unasyn®
View full Ampicillin-Sulbactam page →
Ertapenem
???
Your EMR may offer you a “helpful” allergy warning when ordering a carbapenem because your patient is allergic to penicillins or cephalosporins; the cross reactivity is very low and most people tolerate carbapenems with a low risk of allergic reaction.
1 g IV q24h
IV / IM
1 g vial
BrandsGeneric, Invanz®
View full Ertapenem page →
Piperacillin-TazobactamNon-pseudomonal dose
???
3.375 g IV q6h
IV
2.25 g3.375 g4.5 g
BrandsGeneric, Zosyn®
View full Piperacillin-Tazobactam page →
Aztreonam AND Metronidazole
Do NOT give aztreonam to those with a Ceftazidime₃ allergy (shared side chain → cross-reactivity).
Aztreonam has 'some' antipseudomonal activity.
Aztreonam2 g IV q8h
Metronidazole500 mg IV q8h
Ceftazidime₃ AND MetronidazoleNon-pseudomonal dose
Ceftazidime₃1 g IV q8h
Metronidazole500 mg IV q8h
Ceftriaxone₃ AND Metronidazole
Ceftriaxone₃1 g to 2 g IV q24h
Metronidazole500 mg IV q8h
Moxifloxacin AND Metronidazole
Moxifloxacin400 mg IV q24h
Metronidazole500 mg IV q8h
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Anti-MRSA
DaptomycinMRSA and VRE
???
4 mg to 6 mg/kg/day IV q24h
IV
350 mg vial500 mg vial
BrandsGeneric, Cubicin®
View full Daptomycin page →
LinezolidMRSA and VRE
???
PO and IV have the same bioavailability.
600 mg IV/PO q12h
Tablets
600 mg
Liquid
100 mg/5 mL
IV
600 mg/300 mL
BrandsGeneric, Zyvox®
View full Linezolid page →
VancomycinMRSA
???
Rounding to nearest 250 mg is common and based on actual body weight.
15 mg/kg IV q8h to q12h + therapeutic monitoring
20 mg/kg IV q8h to q12h + therapeutic monitoring

Consider a loading dose in critically ill patients
25 mg/kg IV (loading dose)
30 mg/kg IV (loading dose)
IV
500 mg750 mg1 g1.25 g5 g
Capsules — PO, C. diff only
125 mg250 mg
BrandsGeneric, Vancocin®
View full Vancomycin page →

Drug Info

IV / IM
1 g vial2 g vial
Inhaled (Cayston®)
75 mg
BrandsGeneric, Azactam®, Cayston® (inhaled)

Safety

?PregnancyNot yet reviewed.
?BreastfeedingNot yet reviewed.
?WarfarinNot yet reviewed.