Abx drug review Flashcards by josh urness

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

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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

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B-Lactams

Penicillin, Aminopenicillins (ampicillin and amoxicillin), Penicillinase-resistant penicillins (dicloxacillin, nafcillin), extended spectrum penicillins (pepercillin, ticarcillin)

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Penicillin: MOA, indications and AE

MOA: Inhibits cell wall synthesis
Indications: Gram pos: streptococci. Only Gram neg: Neisseria meningitidis. Syphillis

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Aminopenicillins

Ampicillin, amoxicillin: Better absorbed than penicillin

Indications: Streptococci, enterococci

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Penicillinase-resistant penicllins

Dicloxacillin, nafcillin. Covers staph

Indications: major drug of choice for MSSA, also works for strept

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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.,

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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.

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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

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Cephalosporins

MOA: Inhibit cell wall synthesis and more resistant to Beta lactamases.
Altered penicillin binding proteins
4 generations

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1st generation cephalosporins

Cephazolin and cephalexin (keflex)
Indications: Strep, MSSA,
E.coli, Kleb
Skin infections and some respiratory

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2nd generation cephalosporins

Cefuroxime, cefotetan, cefoxitin
Good for everything great for nothing
Surgical prophylaxsis, broad coverage
Cefotetan and cefoxitin: B. fragilis

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3rd generation cephalosporin

Ceftriaxone, cefotaxime, ceftazidime
Diminished gram pos coverage, good gram neg coverage.
Ceftazidime: good coverage for Pseudomonas

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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

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Ceftaroline

Cephalorsporin that doesn’t fit into generations

A gram positive drug that covers MRSA and strep pneumo

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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.