Abx drug review

Question 1

Doxycycline

Answer 1

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

Question 2

Trimethoprim/sulfamethoxazole

TMP/SMX

Answer 2

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

Question 3

B-Lactams

Answer 3

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

Question 4

Penicillin: MOA, indications and AE

Answer 4

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

Question 5

Aminopenicillins

Answer 5

Ampicillin, amoxicillin: Better absorbed than penicillin

Indications: Streptococci, enterococci

Question 6

Penicillinase-resistant penicllins

Answer 6

Dicloxacillin, nafcillin. Covers staph

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

Question 7

Extended spectrum penicillins

Answer 7

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.,

Question 8

Penicillin plus B lactamase inhibitor

Answer 8

Amoxicillin plus clavulanate: Augmentin
Increase MSSA coverage, add enterobacteriaceae.
Good for all anaerobe coverage
Think adding gram negative and anaerobic coverage.

Question 9

Adverse effects of penicillins

Answer 9

Common: allergic: anaphylaxsis, rash, urticaria, fever.
- Diarrhea
Less common:
- Hematologic, thrombocytopenia
- Hepatitis/biliary and interstitial nephritis: nafcillin/oxacillin
- Seizures: high doses

Question 10

Cephalosporins

Answer 10

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

Question 11

1st generation cephalosporins

Answer 11

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

Question 12

2nd generation cephalosporins

Answer 12

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

Question 13

3rd generation cephalosporin

Answer 13

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

Question 14

4th generation cephalosporin

Answer 14

Cefepime: used for serious hospital infections
Good gram neg and pos
Strept and MSSA
Psuedomonas on down for neg
Anaerobes: oral only

Question 15

Ceftaroline

Answer 15

Cephalorsporin that doesn’t fit into generations

A gram positive drug that covers MRSA and strep pneumo

Question 16

Which cephalosporins cover enterococci?

Answer 16

None of the generations cover enterococci

Question 17

Oral cephalosporins indications

Answer 17

Streptococcus pneumoniae
Haemophilus influenza
Not as well absorbed as IV forms of cephalosporins

Question 18

Carbapenems

Answer 18

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

Question 19

Aminoglycosides

Answer 19

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

Question 20

Aminoglycosides AE

Answer 20

Nephrotoxicity
Ototoxicity
Neuromuscular paralysis
Do not use in patients with motor endplate disorders

Question 21

Fluoroquinlones

Answer 21

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

Question 22

Fluroquinlones AEs?

Answer 22

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)

Question 23

Macrolides

Answer 23

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

Question 24

Macrolide AE

Answer 24

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

Question 25

Metronidazole

Answer 25

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

Question 26

Clindamycin

Answer 26

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

Question 27

Vancomycin, Linezolid, Daptomycin

Answer 27

Gram positive drugs: strept and staph including MRSA

Question 28

Vancomycin

Answer 28

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

Question 29

Linezolid

Answer 29

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

Question 30

Daptomycin

Answer 30

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.