Antimicrobial Quick Reference

OVERVIEW

Format:

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

ANTI-BACTERIALS

Amikacin

• 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

Amoxycillin

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

Amoxicillin-clavulanate

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

Ampicillin

• 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

Azithromycin

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

Aztreonam

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

Benzylpenicillin

• 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

Cefepime

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

Ceftazidime

• 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

Cefuroxime

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

Ceftriaxone

• 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

Cephazolin

• 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

Ciprofloxacin

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

Clarithromycin

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

Clindamycin

• 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)

Co-trimoxazole

• 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,

Doxycycline

• 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

Erythromycin

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

Flucloxacillin

• 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

Gentamicin

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

Imipenem-cilastatin

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

Linezolid

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

Meropenem

• 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

Metronidazole

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

Moxifloxacin

• 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

Nitrofurantoin

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

Norfloxacin

• – 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

Quinupristin/dalfopristin

• 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

Rifampicin

• 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

Roxithromycin

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

Teicoplanin

• 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

Telavancin

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

Tetracycline

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

Tigecycline

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

Tircarcillin

• 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

Tobramycin

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

Vancomycin

• 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

ANTI-VIRAL

Acyclovir

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

Alpha-interferon

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

Amantadine

• 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

Famciclovir

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

Foscarnet

• 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

Gancicilovir

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

Valaciclovir

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

Oseltamivir

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

Ribavirin

• 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

ANTI-FUNGALS

Amphortericin B

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

Caspafungin

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

Fluconazole

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

Itraconazole

• 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

Nystatin

• polyene
• Candida albicans
• topical application

Voriconazole

• 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

ANTI-PARASITICS

Albendazole

• 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

Ivermectin

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

Mebendazole

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

Metronidazole

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

ANTI-PROTOZOANS

Aretemether + Lumefantrine

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

Artesunate

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

Atrovaquone + proguanil

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

Clindamycin

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

Doxycycline

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

Mefloquine

• 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