Intro to Infectious Diseases Pharmacotherapy

• Prevention of an infection
• ex. prior to intraabdominal surgery

• Have idea of what causes but don't know for sure
• Most antibiotic use

• Know what you are treating
• ex. PCN shot for syphilis

• 1) Is infection present? What is evidence? (Epidemology, Pathophysiology, Clinical Presentation, Diagnostic workup)
• 2) Obtain cultures for micro lab
• 3) Start empirical antibiotics (Which pathogens likely to cause this infectious syndrome?)
• 4) Review gram stain, organism(s) ID & susceptibility reports from lab
• 5) Narrow your therapy bassed on culture results (monitoring parameters, watching for side effects, avoiding DDI, looking for clinical improvement)
• 6) Stop therapy when appropriate

• Fever
• H&P
• WBC w/ diff
• S/s

• Controlled elevation in body temp above normal
• Normal 98-98.6*
• Rectal 0.6 higher, axilla 0.6 lower
• Not harmless unless > 105*

• Most infections assoc. w/ leukocytosis
• Normal WBC 4.5-9.5
• Bacterial infections- increase PMN % & presence of neutraphils (Left shift)
• Viral, fungal, TB- Lymphocytosis
• Parasites, allergies- eosinophilia

• Vary depending on infection
• Ex- cellulitis: swelling, erythema of skin, tenderness, drainage
• UTI- pain on urination ( dysuria)
• Pneumonia- cough

• chest xray
• MRI
• CT

• Taken in acutely ill, febrile (sick enough to be hospitialized)
• 2 sets of blood culture, one hour apart from 2 different peripheral sites (anaerobic & aerobic)

• Thorough H&P
• Where infection acquired?
• Immunocompetant vs. immunosuppressed
• Pets? Sick contacts? Travel?
• Drug allergies?
• Age
• Liver & renal fxn
• Pregnancy & lactation
• Metabolic abnormalities
• Concomitant drugs and disease states

• Tissue penetration
• efficacy
• route, bioavailability
• Bacteriocidal vs bacteriostatic
• SE & DDI
• Cost & insurance

• Monitor fever
• Resolution of S/S of infection
• Normalizing of WBC & vital signs

lowest antimicrobial concentration that prevents visible growth of an organism after approx 24 hours of incubation in a specified growth medium

• Streptococcus
• Staphylococcus epidermidis
• Corynebacterium
• Propionibacterium

• Viridans streptococcus
• Peptococcus
• Peptostreptococcus
• Candida

• S. pneumoniae
• S. pyogenes
• Neisseria
• H. influenzae
• S. aureus (nose)

Should not have any

• Enterococcus
• Lactobacillus
• Candida

• Enterococcus
• Lactobacillus
• Bacteroides
• Enterobacteriaceae
• *more anaerobic environment further down

• Enterococcus
• Lactobacillus
• Bacteroides
• Enterobacteriaceae
• Streptococcus
• Clostridia
• Candida

• Lactobacillus
• Prevotella
• Enterobacteriaceae
• Group B strep
• Staph
• Candida

• Penicillins
• Penicillinase Resistant Penicillins
• Beta lactam/ beta lactamase inhibitor combinations
• cephalosporins
• carbapenems
• monobactam

• Treponema pallidum (syphilis)- DOC
• Strep (A, B, C, F, G)- 100% susceptible
• Strep pneumoniae -65% susceptible

• Penicillin G- IV
• Penicillin VK- oral
• Bi-cillin LA- IM
• Procain penicillin- IM
• Bi-cillin CR- IM

• Amoxicillin
• Ampicillin
• Ticarcillin
• Piperacillin

• Enterococcus (most active)
• Listeria monocytogenes (DOC)

• Pseudomonas aeruginosa
• Similar to PCN for gram (+)

• Nafcillin
• Oxacillin

MSSA

• Unasyn (Ampicillin/ sulbactam)
• Augmentin (amoxicillin/ clavulanate)
• Zosyn (piperacillin/ tazobactam)

• MSSE
• MSSA
• Streptococcus
• Enterococcus
• Anaerobes (mouth, gut)
• Some GNR- E. coli, klebsiella, proteus, haemophilus

• Strep
• MSSA
• MSSE
• Enterococcus
• Anaerobes (mouth, gut)
• Excellent, broad gram (-) including Enterobacteriaceae
• Pseudomonas

• Imipenen/ cilastin (primaxin)
• Meropenem (Merrem)
• Doripenem (Doribax)
• Ertapenem (Invanz)**
• **Cannot be used interchangably with others

• Most stable to Beta-lactamases
• DOC ESBL- Klebsiella, E coli
• High dose Imipenem/ cilastin--> seizures
• Covers broad aerobic gram (+), aerobic gram (-), including:
• -Acinetobacter
• -Pseudomonas
• -Anaerobes

• Does not cover Acinetobacter or pseudomonas
• Cannot be used interchangably with other carbapenems

• Aztreonam
• (not a beta- lactam)

• Only gram (-) activity
• Pseudomonas
• **Useful for severe beta lactam allergy

• Allergic rxns (SJS)
• Interstitial nephritis (Nephrotoxicity)
• Seizures
• Thrombocytopenia**
• Adjust for renal dysfunction**
• Back up oral contraception**
• Clostidium difficile super infection**
• **Can be applied to any antibiotic

• PCN to Cephalosporin- 3-5%
• PCN to Carbapenem- 11-50%
• If IgE mediated or SJS hx AVOID!!
• Desensitization protocols

• Cephalexin
• Cefazolin

• Streptococcus
• Staphylococcus
• MRSA

• Oral:
• -Cefaclor
• -Cefuroxime
• Parenteral:
• -Cefoxitin
• -Cefuroxime

• Strep
• MSSA
• GNR
• Bacteriodes (GI use)

• Cefuroxime (IV/PO)
• Cefaclor (PO)

• Strep
• MSSA
• some GNR
• *Lack bacteroides

• Oral:
• -Cefdinir
• Parenteral:
• -Ceftazidime
• -Ceftriaxone

• Enterobacteriaceae
• Pseudomonas

• Great strep
• MSSA
• Nisseria
• Haemophilus
• Moraxhella catarrhalis
• Enterobacteriaceae
• **No pseudomonas

Cefepime (IV)

• IV
• Strep
• MSSA, MSSE
• Enterobacteriaceae
• Pseudomonas

Ceftaroline

• IV
• Streptococcus
• MSSA
• MRSA
• Enterobacteriacese
• H. Influenzae
• **Only cephalosporin that covers MRSA

• Allergy
• **Neutropenia
• Drug fever
• **Biliary sludging (ceftriaxone)
• **N-methylthiotetrazole (MTT) side chain found in cefotetan, cefamandole, inhibits vit K production, disulfiram reaction

• Vancomycin
• Telavancin

• IV, oral
• MRSA- gold standard
• MSSA
• Strep
• Enterococcus
• **Clostridium difficile--> oral vancomycin only
• No gram (-)

• Redman syndrome
• Allergic rxn
• Nephrotoxicity at higher doses
• Ototoxicity

Contra-indicated in pregnancy

• PO/ IV
• Gram (+) specialist
• MRSA
• Staph
• Strep
• Enterococci
• VRE

• Serotonin syndrome with SSRI's and other antidepressants
• Myeloxuppression (Black box warning)
• - Weekly CBC
• Permanent peripheral neuropathy & optic neuropathy with prolonged use

• Amikacin
• Tobramycin
• Gentamicin
• Streptomycin (Parenteral, nebulized)

• Enterobacteriaceae
• Pseudomonas
• Acinetobacter
• (Gram (-) rod specialist)
• *provides synergy with beta lactams

• Nephrotoxicity
• Ototoxicity

• Norfloxacin
• Ofloxacin
• Ciprofloxacin
• Levofloxacin
• Moxifloxican

• IV, PO, ophthalmic, otic
• Excellent gram (-) activity
• Pseudomonas
• Not useful for most gram (+)
• exception Bacillus anthracis (anthrax)- DOC

• Teriffic Strep pneumoniae
• Same gram (-) as cipro
• No anaerobic coverage
• Atypicals
• 2nd line in TB

• Adds anaerobic coverage against bacteroides
• strep pneumoniae
• anaerobes
• some gram (-)
• mycoplasma
• legionella
• chlamydia
• TB
• **No pseudomonas activity

• Confusion (elderly)
• Allergic rxn
• QT prolongation
• **Photosensitivity
• **Tendon rupture
• **Absolute CI- pregnancy, relative in pediatrics
• Chelating agents (iron, Ca2+, Mg2+), dairy, tube feedings (**separate by a couple of hours)

• Erythromycin (PO/ IV)
• Azithromycin (PO/IV)**
• Clarithromycin (PO)**
• **Advanced generation

• Strep
• Moraxella
• H. influenzae
• atypical bacteria

Better H. influenzae/ Legionella

• N/V (erythromycin worst)
• Bitter taste in mouth (Clarithromycin)
• Inhibits CYP 3A4
• QT prolongation
• Prokinetic agent

• IV, PO, topica, intravaginal
• Strep
• Staph
• Anaerobes
• MRSA

• diarrhea
• Clostridium difficile (#1 associated w/)

• IV only
• Gram (+) activity only
• MRSA
• VRE
• **Weekly CPK monitoring (rhabdomyolysis)

Synercid (Quinupristin/ dalfopristin)

• Gram (+) only
• MRSA
• VRE faecium
• **Associated w/ severe myalgias

• Tetracycline (PO)
• Doxycycline (IV/ PO)
• Minocycline (PO)

• Avoid use in children <9 yo (tooth discoloration)
• Photosensitivity
• Avoid iron, antacids, dairy
• Empty stomach

• MRSA skin infection
• Lyme disease
• Chlamydia
• Atypicals
• Malaria Prophylaxis

• IV only
• Broad coverage:
• -Atypicals
• -Enterococci
• -Staph
• -Strep
• -Anaerobes
• -Most enterobacteriaceae
• VRE
• MRSA
• *N/V (30%)

• IV/ PO
• **Dose based on TMP component only
• Pneumocystis jiroveci (carinii)- DOC
• MRSA
• Enterobacteriaceae
• Common uses: UTI, MRSA

• Dermatological (SJS)**
• Photosensitivity
• Avoid us with warfarin
• Do not give if G6PD deficient, pregnancy at term or to newborn

• Use: Lower UTI only
• E. coli
• S. saprophyticus
• Klebsiella

• CI Cr< 50 ml/min
• Pulmonary fibrosis
• peripheral neuropathy

• Metronidazole
• Tinidazole

• IV/ PO/ Vaginal gel
• Anaerobic specialist
• Great for gut anaerobes (Bacteriodes spp)
• Trichomonas, Giardia (1st line)
• C. difficile (1st line mild-mod)

• N/V
• avoid w/ warfarin
• Disulfiram reactions w/ alcohol

• IV, Otic, Ophthalmic preps
• Toxicities: gray syndrome

• Ceftaroline
• Vancomycin
• Linezolid
• Daptomycin
• Streptogramins (Synercid)
• Tetracyclins
• Tigecycline
• Bactrim
• Clindamycin

• Carbapenems (except Ertapenem)
• Aztreonam
• Zosyn
• Ceftazidime
• Cefepime
• Piperacillin
• Aminoglycosides
• Ciprofloxacin
• Levofloxacin
• Amikacin

• Macrolides
• Fluoroquinolones
• Tetracyclines