Antimicrobial Quick Reference



  • Name (alphabetical order)
  • class
  • activity against
  • dose
  • issues with use
    -> major gaps in cover



  • aminoglycoside
  • Gram –ve organisms (including Pseudomonas) + some Gram +ve cover
  • 7.5mg/kg Q12 hrly (titrated to troughs)
  • nephrotoxic, ototoxic, peripheral neuritis, neuromuscular blockade potentiation
    -> used for gram negatives


  • moderate-spectrum penicillin
  • gram +ve + improved cover against gram –ve bacilli
  • 1g Q4 hrly
  • rash with EBV
    -> staphylococcus and gram negatives


  • broad spectrum penicillin
  • gram +ve’s, anaerobes, aerobic gram –ve bacilli
  • 1.2g Q6 hrly
  • platelet dysfunction, blood dyscrasia
    -> MRSA


  • broad spectrum penicillin
  • Gram +ve and Gram –ve organisms (ineffective against Beta-lactamase producers)
  • 500mg IV Q4 hourly
  • GI upset, rash
    -> staphylococcus and gram negatives


  • macrolide
  • anaerobes and non-enteric gram negatives
  • 10mg/kg LD Q24hrly -> 5mg/kg on subsequent days
  • nephritis, hepatitis
    • -> gram positive, atypical mycobacteria and toxoplasma


  • monobactam
  • aerobic gram –ve including Pseudomonas
  • 2g Q6 hrly
  • phlebitis, hepatitis, thrombocytopaenia
    > gram positives


  • a narrow spectrum penicillin
  • gram +ve (streptococcus pneumoniae, listeria)
  • 1-5g/day in divided doses
  • increased Na+, decreased K+, GI upset – pseudomembranous colitis, seizures, nephritis, blood dyscrasias
    -> inactivated by beta-lactamases -> most staph’s are resistant
    -> streptococcus pneumonia increasing resistance


  • 4th generation cephalosporin
  • gram +ve and gram –ve cover and anaerobes
  • 2g Q8 hourly
  • GI upset, rash


  • 3rd generation cephalosporin (beta-lactam)
  • gram –ve and anaerobes, some gram +ve
  • 2-6g/24 hours in 2 to 3 divided doses (30-100mg/kg/day in divided doses)
    -> reduced gram positive cover


  • 2nd generation cephalosporin with anti-haemophilus cover
  • gram +ve’s + improved gram –ve cover
  • adults 1.5g Q8 hrly, paediatrics 50mg/kg Q6hrly


  • 3rd generation cephalosporin
  • reduced gram +ve with improved gram –ve cover (improved CSF penetration)
  • 50mg/kg Q24hrs
  • reduce in renal failure, avoid in neonates due to biliary excretion


  • 1st generation cephalosporin + beta lactam resistant, all induce ESBL producers
  • gram +ve and some gram –ve cover
  • 15mg/kg Q8 hrly
  • 3-6% cross reactivity with penicillins


  • 2nd generation quinolone
  • predominately gram –ve cover (Pseudomonas)
  • 300mg Q12 hourly
  • growing cartilage damage, achilles tendonitis, QT prolongation
    -> no anaerobic or gram positive cover


  • macrolide
  • helicobacter pylori and mycobacterium avium complex
  • 500mg Q12 hrly
  • hepatitis


  • lincosamide
  • gram +ve’s, anaerobes, some non-enteric gram negative (Helicobacter), intracellular organisms (mycobacterium avium complex)
  • high bone, bile and urine concentrations)
  • 2-4mg/kg Q6 hrly
  • GI upset, elevated LFT’s, blood dyscrasias

Colistin (polymyxin E)

  • polymixin antibiotic
  • gram –ve rods and New Delhi metallo-B-Lactamase mutli-resistant Enterobacteriaceae
  • two forms with different dosing regimes
  • nephrotoxic and neurotoxic
    -> gram negatives not reliably covered: Proteus, Providencia, Serratia, Neisseria, Moraxella, Helicobacter, Brucella, Burkholderia, Stenotrophomonas (some strains)


  • sulphamethoxazole + trimethoprim
  • sulphonamide
  • gram +ve and gram –ve cover and protozoan
  • covers Pneumocystitis jiroveci, Stentrophomonas maltophila, Listeria monocytogenes, Norcardia
  • 25-100mg/kg of sulphamethoxazole Q6 hrly (dose varies -> consult ID)
  • SJS, blood dyscrasias, influenzae like symptoms,


  • tetracycline
  • gram +ve and gram –ve but widespread resistance
  • good cover for Chlamydophila, Mycoplasma, Rickettseiae, Spirocheataes, Brucella, Coxiella brunetii
  • 200mg LD -> 100mg Q24 hrly
  • oesophagitis, tooth discolouration in kids, photosensitivity, pancreatitis, hepatitis


  • macrolide
  • gram +ve, anaerobes, non-enteric gram –ve infections, intracellular organisms
  • 20mg/kg/day in divided doses
  • long QT, monomorphic VT, pancreatitis, nephrotoxicity, hepatitis


  • narrow spectrum penicillin with anti-staph cover
  • staph (beta lactamase resistant)
  • 50-100mg/kg/day
  • cholestatic jaundice

Fusidic acid

  • chemically related to the cephalosporins
  • penicillin resistant staphylococcal infections (endocarditis and bone infections)
  • 1g Q8hrly
  • GI upset, jaundice, rashes


  • aminoglycoside
  • aerobic gram –ve’s + pseudomonas coverage
  • 3-5mg/kg LD -> titrate to trough
  •  nephrotoxic, ototoxic, peripheral neuritis, neuromuscular blockade potentiation


  • carbapenem
  • broad spectrum gram +ve, gram –ve and anaerobic cover
  • 500mg Q6 hrly
  • hepatitis, CNS stimulation, rashes
    -> MRSA, VISA, VRSA, atypical pneumonia’s.


  • oxazolidinone
  • gram +ve’s (including multi resistant staphylococci and enterococci)
  • 600mg Q12 hrly
  • blood dyscrasias, GI upset, headache, dry mouth


  • carbapenem
  • broad spectrum gram +ve, gram –ve and anaerobic cover
  • up to 2g Q8 hrly (40mg/kg)
  • hepatitis, CNS stimulation, rashes
    -> MRSA, VISA, VRSA, Enterococcus faecium, Stenotrophomonas and many Pseudomonas, atypical pneumonia’s


  • nitroimidazole
  • anaerobes and protozoa (including Trichomonas, Giardia and Entamobea)
  • 7.5mg/kg Q8 hrly
  • GI upset, rash, dark urine


  • 3rd generation quinolone
  • gram –ve, gram +ve, anaerobic and intracellular organisms of atypical pneumonia
  • 400mg Q24 hrly
  • growing cartilage damage, achillies tendonitis, QT prolongation
    -> Pseudomonas


  • E.coli, Enterococcus, Staph aureus, Citrobacter, Klebsiella
  • 100mg QID PO (5-7mg/kg/day)
  • GI upset, headache, flatus


  • – 2nd generation quinolone
  • – predominantly gram –ve cover
  • – 400mg Q12 hourly
  • – growing cartilage damage, Achilles tendonitis, QT prolongation

Pipericillin-Tazobactam (Tazocin)

  • broad spectrum penicillin
  • gram +ve’s, anaerobes, aerobic gram –ve bacilli (superior enterococcal cover)
  • 4.5g Q8hrly
  • platelet dysfunction, blood dyscrasias
    -> MRSA, VISA, VRSA, multi-resistant gram negatives


  • streptogramins
  • VRSA, VRE, gram positive bacilli (Enterococcus faecium), gram negative aerobes (Neiserria and Moraxella), intracellular organisms
  • 7.5mg/kg Q8 hrly
  • arthalgia, myalgia, GI upset, headaches


  • rifamycin
  • gram +ve and gram –ve, mycobacterium tuberculosis and atypical mycobacteria
  • 10-20mg/kg/day
  • drug reactions: warfarin, OCP, cyclosporine, orange secretions, hepatitis, nephritis, thrombocytopaenia


  • macrolide
  • gram +ve, anaerobes and some non-enteric gram-negative infections, intracellular organisms
  • 300mg Q24 hrly
  • hepatitis


  • glycopeptide
  • MRSA, MRSE, gram +ve, good cover against streptococcus pneumoniae and C.difficile
  • 400mg LD -> 400mg @ 12 hours -> 400mg Q24 hrs
  • nephrotoxicity, blood dyscrasias, ototoxicity


  • derivative of vancomycin
  • gram +ve’s (including MRSA)
  • 10mg/kg Q24 hrs
  • GI upset, metallic taste, headache, foamy urine


  • tetracyclines
  • chlamydia, rickettsia, spirochaete, brucella, mycoplasma, leptospirosis
  • 500mg Q12hrly
  • stained teeth in children, renal impairment, GI upset, hepatic impairment


  • glycylcycline
  • gram +ve’s (VRE, MRSA, MRSE), gram –ve’s (ESBL), anaerobes
  • 100mg LD -> 50mg Q12 hrly
  • GI upset, similar to tetracyclines


  • carboxypenicillin (often in combination with clavulanate)
  • gram –ve organisms (especially Pseudomonas)
  • 3000mg/200mg (tircarcillin/clavulanate) Q4-8 hourly
  • increased Na+, decreased K+, GI upset – pseudomembranous colitis, seizures, nephritis, blood dyscrasias


  • aminoglycoside
  • aerobic gram –ve’s + Pseudomonas coverage
  • 3-5mg/kg/day in 3 divided doses -> monitor
  • nephrotoxic, ototoxic, peripheral neuritis, neuromuscular blockage prolongation


  • glycopeptide derivative
  • MRSA, MRSE, gram +ves, pencillin resistant streptococcus pneumoniae and C. difficile
  • 10mg/kg LD -> dose of plasma concentration
  • red man syndrome, ototoxic, nephrotoxic



  • guanosine analogue
  • viral DNA polymerase inhibitor
  • anti-HSV
  • 10mg/kg Q8hrly
  • rashes, GI upset, hepatic and renal impairement, blood dyscrasias, CNS symptoms


  • interferon
  • used hepatitis B and C and many other diseases
  • SC injection
  • complex dosing
  • flu like symptoms, GI upset, haemodynamic instability, blood dyscrasias


  • M2 channel inhibitor -> disruption of dissociation of viral matrix and riobnucleoprotein
  • anti-viral and anti-parkinsonian drug
  • anti-HSV and anti-influenza
  • for anti-influenzae: 100mg/day
  • GI upset, convulsions, hallucinations


  • guanosine analogue
  • anti-HSV
  • 1500mg OD PO (requires renal adjustment)
  • well tolerated


  • guanosine analogue
  • inhibitor of viron DNA polymerase
  • anti-CMV
  • 20mg/kg IV LD -> 20-120mg/kg according to renal function
  • GI upset, renal failure, hypocalcaemia, convulsions


  • inhibition of CMV DNA polymerase
  • anti-CMV
  • administered as a prodrug (valganciclovir)
  • 5mg/kg Q12hrly IV
  • blood dyscrasias, rash, hepatorenal impairment, GI upset


  • guanosine analogue
  • anti-HSV
  • 1000mg TDS PO
  • headache, nausea, SOB


  • neuraminidase inhibitor
  • anti-influenzae
  • 75mg BD PO
  • GI upset


  • guanosine analogue
  • DNA synthesis inhibitor -> active against many RAN and DNA viruses
  • RSV and Lassa fever
  • 20mg/mL nebulised for 12-18 hours for 3-7 days
  • anaemia, worsening respiratory failure


Amphortericin B

  • polyene
  • all Candida species except C.lustanae + anti-protozoan
  • 0.5-1mg/kg Q24 hr
  • nephrotoxic, hepatotoxic, GI upset, blood dyscrasias


  • echinocandin
  • all Candida species, Aspergillus
  • 70mg LD -> 50mg Q24 hrly
  • GI upset, headache, myalgia, increase in LFT’s,


  • azole
  • Candida albicans and Cryptococcus
  • 50-400mg Q24 hr
  • GI upset, hepatic dysfunction, arrhythmias


  • azole
  • broader anti-fungal activity than fluconazole but not as much as voriconazole – Candida albicans, Cryptococcus, aspergillus
  • 200mg Q12 hrly for 4 doses -> 200mg Q24 hrly
  • increased LFT’s, GI upset


  • polyene
  • Candida albicans
  • topical application


  • azole
  • broadspectrum anti-fungal – Candida albicans, glabrata, krusei, Cryptococcus, Aspergillus
  • 6mg/kg Q12 hourly (loading for 24 hours) -> 4mg/kg Q12 hourly
  • transient visual disturbance, fever, rash, GI upset



  • benzimidzole
  • anti-nematode and cestode (worms)
  • 800mg PO in divided doses (give with fatty meal or grape juice -> increases bioavailability)
  • GI upset, headache, dizziness, hepatic impairment, pancytopaenia


  • synthetic antibiotic derivative
  • anti-nematode
  • 200-400mcg/kg
  • side effects related to parasitic load in host


  • benzimidzole
  • anti-nematode and cestode (worms)
  • 100mg OD PO
  • minimal side-effects


  • nitroimidazole
  • anaerobes and protozoa (including trichomonas, giardia and entamobea)
  • 7.5mg/kg Q8 hrly
  • GI upset, rash, dark urine


Aretemether + Lumefantrine

  • anti-malarial
  • 20/120mg
  • complex dosing


  • IV anti-malarial
  • 2.4mg/kg IV Q 12 hrly

Atrovaquone + proguanil

  • anti-malarial
  • 250/100mg
  • complex dosing


  • lincosamide
  • gram +ve’s and anaerobes (high bone, bile and urine concentrations)
  • 2-4mg/kg Q6 hrly
  • GI upset, elevated LFT’s, blood dyscrasias


  • tetracycline
  • gram +ve and gram –ve but widespread resistance
  • 200mg LD -> 100mg Q24 hrly
  • oesophagitis, tooth discolouration in kids, photosensitivity, pancreatitis, hepatitis


  • anti-malarial
  • 15mg/kg LD -> 500mg Q6 hrly

Quinine sulphate

  • anti-malarial
  • IV 20mg/kg LD over 4 hours -> 10mg/kg Q 8hourly
  • take with doxycycline or clindamycin or atovaquone+proguanil or mefloquine

CCC 700 6

Critical Care


Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of three amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.