Infectious Diseases part 1 Flashcards
Fourth generation Cephalosporins
Cefepime (Maxipime) IV
Further expanded gram-neg coverage
Same + pseudomonas aeruginosa
Very commonly used for serious HAI
Concern for seizure if not dosed properly
Second Generation Cephalosporins
Cefuroxime (Ceftin) PO/ IV
Cefoxitin (Mefoxin) IV
Enhance gram-negative activity
Spectrum: Streptococcus, MSSA, enteric GNR, Haemophilus
Cefoxitin has anerobic gram-negative activity
Class less commonly used
Clinical use: De-escalation when cultures are back, prophylaxis for abdominal surgeries
Vancomycin (Vancocin) – IV, PO
MOA: inhibits cell wall synthesis
Spectrum: gram-positive only, drug of choice for MRSA
Given IV for systemic infections including pneumonia, CNS, UTI, bone, blood
Given PO for C diff associated diarrhea
Use the IV formulation and compound an oral solution
Also available as commercially made capsules, but very expensive
MUST monitor drug levels for efficacy and toxicitiy
ADE: Nephrotoxicity with elevated levels
Rare: ototoxicity – very high levels
Red Man’s Syndrome – histamine mediated reaction secondary to rapid infusions - not an allergic , simply slow the infusion time
Fifth generation cephalosporins
Ceftaroline (Teflaro) IV
Breaks the rule??
Spectrum : covers MRSA, does not cover Pseudomonas
“Ceftriaxone with MRSA coverage”
Approved for pneumonia and skin infections
Currently being studied for other serious infections (bone)
Monobactams
Aztreonam (Azactam) – IV
Inhibit cell wall synthesis
Only covers gram-negative organisms
Spectrum: very broad, including Pseudomonas aeruginosa
Safe to use in PCN allergy
Similar structure to ceftazidime , caution in patients allergic to ceftazidime
Not commonly used empirically due to its lack of gram-positive coverage, high cost
Well tolerated, similar ADE to cephalosporins
Beta-lactamase Inhibitors
Amoxicillin-clauvulanate (Augmentin)
Ampicillin-sulbactam (Unasyn)
Piperacillin-tazobactam (Zosyn)
inhibit the activity of the beta-lactamases
preserves the spectrum of the agent it’s combined with
Unasyn and Zosyn are IV, Augmentin PO
Used empirically for hospital infections
Augmentin = high rates of diarrhea
Very commonly used
Daptomycin (Cubicin) – IV
MOA: causes rapid depolarization leading to inhibition of protein, DNA and RNA synthesis
Spectrum: ONLY gram-postiive organisms including MSSA, MRSA, VRE
Clinical Uses: Alternative agent to linezolid for resistant gram-positive infections
NOT used to treat pneumonia (inactivated by lung surfactant)
ADE: associated with myopathy, monitor CPK
Dose largely dependent on MIC, do not assume sensitivity
Metronidazole (Flagyl) IV, PO
MOA : interferes with DNA synthesis
Spectrum: anaerobic gram-negative organisms, C. diff
First line recommendation for mild C. diff
Use in combo with vancomycin for severe C. diff
ADE: GI upset, metallic taste, headache, dark urine, peripheral neuropathy
Exhibits a disulfiram-like reaction, do not take with ETOH, will cause severe vomiting
Excellent bioavailability, IV and PO interchangeable
Used for distal colon infections
Cephalosoporins ADE
Overall well tolerated
Hypersensitivity less commonly seen
5-10% cross reactivity see in those allergic to PCNs
Clinically ok to challenge if patient experienced rash
Anaphylaxis, request allergy testing or avoid
GI intolerance (diarrhea)
Seizure in not dosed properly (Cefepime more common)
Neutropenia with long term use
Anti-Staphylococcal Penicillin
Oxacillin Nafcillin Created to tx PCN-resistant Staph aureus Methicillin d/c because toxic Spectrum: MSSA , drug of choice for serious MSSA infections Very short half-life, dosed every 4 hours Cleared by liver, no renal adjustments *other beta lactams renally adjusted Oral option (dicoloxacillin) rarely used
Natural Penicillin (Penicillin V, Penicillin G)
Spectrum: staph aureus (PCN-susceptible), streptococcus, syphilis
No gram-negative activity
Initiallly excellent for skin infections
RESISTANCE
Available in IV and IM as Peniciilin G ,
V is oral form (low absorption)
Total Exposure drugs
Azithromycin
Vancomycin
Polymyxin B / Colistin - IV
MOA: Alters charge of the cell membrane and leads to increased permeability of the membrane -> cell death
Spectrum: broadest antibiotic available to treat gram-negative organisms
Used as a last line resort for multi-drug resistant GNRs
MUST always be used in combo with other antibiotics to px resistance
ADE: nephrotoxicity , respiratory paralysis (rare)
Clindamycin (Cleocin) – IV , PO
MOA: Inhibits protein synthesis
Spectrum: Broad gram-positive (including MRSA) anaerobic pathogens (including oral pathogens) and minimal gram-negative (mainly anaerobic enteric gram-negative organism)
Used in patients with penicillin allergies for skin infections
ADE: GI upset (high rates of diarrhea)
First Generation Cephalosporins
Cephalexin (Keflex) –PO
Cefazolin (Ancef) – IV
Alternative to anti-staphylococcal penicillins
Spectrum: Streptococcus, Staph aureus (MSSA)
Minimal gram-negative activity – resistance
Short ½ life , dosed 3 – 4 x a days
Very common for skin infections and prophylaxis prior to surgeries