Abx drug review Flashcards
Doxycycline
MOA: A tetracycline: reversibly binds to 30S ribosome protein
Indications: Strep, MSSA.
- Respiratory: Strep p., Hflu, atypicals (chlamydia pneumoniae, legionella, mycoplasma p.)
Spirochettes: borrelia burgdorfer (lyme),
Gram Neg: vibrio cholerae (cholera), rickettsia rickettsii (RMSF)
AE: Photosenstivity, N/D, tooth discoloration in kids
Trimethoprim/sulfamethoxazole
TMP/SMX
MOA: inhibits folic acid synthesis via enzyme inhibition
Indications: Wide spectrum but not deep, often UTI and E.coli.
Strept, MSSA, most Enterobacteriacae (think UTI and GI infections), PCP pneumocystic pneumonia
AE: Allergy, GI, neutropenia, thrombocytoopenia
B-Lactams
Penicillin, Aminopenicillins (ampicillin and amoxicillin), Penicillinase-resistant penicillins (dicloxacillin, nafcillin), extended spectrum penicillins (pepercillin, ticarcillin)
Penicillin: MOA, indications and AE
MOA: Inhibits cell wall synthesis
Indications: Gram pos: streptococci. Only Gram neg: Neisseria meningitidis. Syphillis
Aminopenicillins
Ampicillin, amoxicillin: Better absorbed than penicillin
Indications: Streptococci, enterococci
Penicillinase-resistant penicllins
Dicloxacillin, nafcillin. Covers staph
Indications: major drug of choice for MSSA, also works for strept
Extended spectrum penicillins
Piperacillin, Ticaracillin.
Coverage extends to cover gram neg.
Broad spectrum, good for severe infections
Indications: Covers staph, strept, enterococci, also gram neg: through psuedomonas a.,
Penicillin plus B lactamase inhibitor
Amoxicillin plus clavulanate: Augmentin
Increase MSSA coverage, add enterobacteriaceae.
Good for all anaerobe coverage
Think adding gram negative and anaerobic coverage.
Adverse effects of penicillins
Common: allergic: anaphylaxsis, rash, urticaria, fever.
- Diarrhea
Less common:
- Hematologic, thrombocytopenia
- Hepatitis/biliary and interstitial nephritis: nafcillin/oxacillin
- Seizures: high doses
Cephalosporins
MOA: Inhibit cell wall synthesis and more resistant to Beta lactamases.
Altered penicillin binding proteins
4 generations
1st generation cephalosporins
Cephazolin and cephalexin (keflex)
Indications: Strep, MSSA,
E.coli, Kleb
Skin infections and some respiratory
2nd generation cephalosporins
Cefuroxime, cefotetan, cefoxitin
Good for everything great for nothing
Surgical prophylaxsis, broad coverage
Cefotetan and cefoxitin: B. fragilis
3rd generation cephalosporin
Ceftriaxone, cefotaxime, ceftazidime
Diminished gram pos coverage, good gram neg coverage.
Ceftazidime: good coverage for Pseudomonas
4th generation cephalosporin
Cefepime: used for serious hospital infections Good gram neg and pos Strept and MSSA Psuedomonas on down for neg Anaerobes: oral only
Ceftaroline
Cephalorsporin that doesn’t fit into generations
A gram positive drug that covers MRSA and strep pneumo
Which cephalosporins cover enterococci?
None of the generations cover enterococci
Oral cephalosporins indications
Streptococcus pneumoniae
Haemophilus influenza
Not as well absorbed as IV forms of cephalosporins
Carbapenems
Imipenem, meropenem, etc.
Similar in function and structure to beta lactams.
Hardened against beta lactams.
Good against gram negatives and anaerobes.
Also work against strept and MSSA
Broad spectrum good for severe infections
Aminoglycosides
Streptomyicin, gentamyicin MOA: ribosome inhib 30S subunit Great gram neg including Psuedomonas No gram pos coverage no anaerobic coverage Used in combo with gram pos coverage IV only for systemic issues Used topically for ears and eyes
Aminoglycosides AE
Nephrotoxicity
Ototoxicity
Neuromuscular paralysis
Do not use in patients with motor endplate disorders
Fluoroquinlones
Ciprofloxacin, Levofloxacin,moxi, gemi
MOA: Inhibits DNA sythesis by inhibiting DNA gyrase and topoisomerase IV
Respiratory: Levo, moxi, gemi because they cover the atypicals
Non-respiratory: Cipro (doesn’t cover strepP)
Gram positive and gram neg, not anaerobic
Fluroquinlones AEs?
Common: GI: nausea, CNS: HA, dizziness, insomnia
Uncommon:
Cartilage toxicity, CNS: confusion, seizures
Rare cases of tendon rupture (think about in muscle bound individules
Glucose abnormalities
Prolong QT (think about if people are already on antiarrhythmic drugs)
Macrolides
Erythromycin, Clarithromycin, azithromycin
MOA: Ribosomal protein synthesis inhibitor 50s
Indications: good coverage for respiratory infections: strep p., H.flu. plus atypicals: legionella, chlamydia p., mycoplasma p.
Not great MSSA coverage
Macrolide AE
Erythromycin: poorly tolerated
Azithromycin: best tolerated
Common: N/V/D, prolonged QT
Azithromycin does not require renal adjustment
Erythromycin is rarely used now because of the AEs
Metronidazole
Mainstay of treatment for anaerobic infections and treatment of choice for mild to moderate C.diff
Drug of choice for: amebic infections. also used for: giardia, trichomonas vaginalis.
AE: N/V/epigastric distress/abdominal cramps, metallic taste, yeast infection of mouth
Uncommon: neurotoxicity (dizziness, vertigo, numbness or paresthesia.
Cannot be taken with EtoH, = disulfram-like reaction
Clindamycin
Bookend coverage: strep, MSSA and anaerobic including B. fragilis
Similar action to macrolides but not chemically similar
MOA: similar to macrolides, effecting 50s subunit
AE: GI, diarrhea and C.diff
Vancomycin, Linezolid, Daptomycin
Gram positive drugs: strept and staph including MRSA
Vancomycin
MOA: inhibits cell wall synthesis by blocking glycopeptide polymerization
Drug of choice for MRSA
Indic: strept, all staph, somre enterococci
AE: red man syndrome, nephrotoxicity with other agents, ototoxicity with high concentrations
Linezolid
MOA: inhibits 23s ribosomal RNA of 50s subunit
Indic: strept, staph, enterococcus
Gram pos only, no gram neg or anaerobes
Drug of choice for VRE
AE: thrombocytopenia, anemia, neutropenia
Daptomycin
Cyclic lipopeptides
MOA: binds to cell membranes causing rapid depolarization, inhibits intracellular synthesis of DNA, RNA and protein.
Bacteriacidal
Indication: gram positives only, serious infections
Strept, all staph, all enterococcus (use for VRE only)
No anaerobic coverage
AE: GI: D/V/Constipation, anemia
Should never be used in pneumonia because it is inactivated by pulmonary surfactants.
