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Flashcards in Antibiotics Deck (64):
1

Penicillin G, V Mechanism

β-lactam antibiotics
Bind PBP (transpeptidases).
Block transpeptidase cross-linking of peptidoglycan in cell wall.
Activate autolytic enzymes.

2

Penicillin G, V clinical use

Strep and gonorrhea

3

Penicillin G, V Toxicity

Hypersensitivity reactions, hemolytic anemia.

4

Amoxicillin, ampicillin (aminopenicillins) clinical use HHELPSS

H. influenzae, H. pylori, E. coli, Listeria monocytogenes, Proteus mirabilis, Salmonella, Shigella, enterococci.

5

Amoxicillin, ampicillin (aminopenicillins) toxicity

Hypersensitivity reactions; diarrhea

6

Dicloxacillin, nafcillin, oxacillin (penicillinase-resistant) clinical use

Strep and Staph (except MRSA)

7

Dicloxacillin, nafcillin, oxacillin (penicillinase-resistant) toxicity

Hypersensitivity reactions, interstitial nephritis.

8

Piperacillin, ticarcillin clinical use

only PCN for PSEUDOMONAS
Strep
SPACE
PEcK

9

Piperacillin, ticarcillin toxicity

Hypersensitivity reactions.
Ticarcillin Na+ overload
dose dependent platelet dysfunction

10

β-lactamase inhibitors CAST mnemonic

Clavulanic Acid, Sulbactam, Tazobactam.
Often added to penicillin antibiotics to protect the antibiotic from destruction by β-lactamase

11

Cephalosporins (generations I–V) Mechanism

β-lactam drugs that inhibit peptidoglycan cross-linking

12

Organisms typically not covered by cephalosporins are LAME and the exception

Listeria, Atypicals (Chlamydia, Mycoplasma, Legionella), MRSA, and Enterococci.

Exception: ceftaroline covers MRSA and enterocci

13

1st generation Cephalosporin (cefazolin, cephalexin) clinical use (PEcK mnemonic)

staph, strep

Proteus mirabilis, E. coli, Klebsiella pneumoniae.

Cefazolin used prior to surgery to prevent S. aureus wound infections.

14

2nd generation Cephalosporin (cefoxitin, cefotetan, cefuroxime) (HEN PEcKS mnemonic)

staph, strep

H. influenzae, Enterobacter aerogenes, Neisseria spp., Proteus mirabilis, E. coli, Kleb. pneumoniae, Serratia marcescens.

TANFOX - anaerobes

15

3rd generation Cephalosporin (ceftriaxone, ceftazidime) clinical use

serious gram-negative infections, S(P)ACE

community acquired and nosocomial pneumonia

Meningitis

Ceftriaxone—meningitis, gonorrhea
Ceftazidime—Pseudomonas

16

4th generation Cephalosporin (cefepime)

staph, strep
SPACE
fever in neutropenia

17

5th generation Cephalosporin (ceftaroline)

staph, strep,
MRSA
enterococcus

18

Cephalosporin toxicity

Hypersensitivity reactions, autoimmune hemolytic anemia, disulfiram-like reaction, vitamin K deficiency. Exhibit cross-reactivity with penicillins.􏰃nephrotoxicity of aminoglycosides.

19

Carbapenems (Imipenem, meropenem, ertapenem, doripenem) mechanism

Binds to PBP-1 and PBP-2, B-Lactamase resistant

Always administered with cilastatin (inhibitor of renal dehydropeptidase I) to􏰄 decrease inactivation of drug in renal tubules.

20

Imipenem mnemonic

With imipenem, “the kill is lastin’ with cilastatin.”

21

Carbapenem (Imipenem, meropenem, ertapenem, doripenem) clinical use

Gram-positive cocci, gram-negative rods, and anaerobes.

significant side effects limit use to life-threatening infections or after other drugs have failed.

Meropenem has a decreased 􏰄risk of seizures and is stable to dehydropeptidase I.

22

Carbapenem (Imipenem, meropenem, ertapenem, doripenem) toxicity

GI distress, skin rash, and CNS toxicity (SEIZURES)

23

Vancomycin Mechanism

Inhibits cell wall peptidoglycan formation by binding D-ala D-ala portion of cell wall precursors.

Bactericidal.

Not susceptible to β-lactamases.

24

Vancomycin clinical use

Gram-positive bugs only—serious, multidrug-resistant organisms.

Clostridium difficile (oral dose for pseudomembranous colitis).

25

Vancomycin Toxicity (NOT mnemonic)

Nephrotoxicity, Ototoxicity, Thrombophlebitis

Red Man Syndrome (can largely prevent by pretreatment with antihistamines and slow infusion rate).

26

Aminoglycosides (Gentamicin, Neomycin, Amikacin, Tobramycin, Streptomycin) mechanism

Bactericidal; irreversible inhibition of initiation complex through binding of the 30S subunit.

Messes with LPS

Require O2 for uptake; therefore ineffective against anaerobes.

27

Aminoglycosides (Gentamicin, Neomycin, Amikacin, Tobramycin, Streptomycin) clinical use

Severe gram-negative infections.

Neomycin for bowel surgery.

28

Aminoglycosides (Gentamicin, Neomycin, Amikacin, Tobramycin, Streptomycin) toxicity

Nephrotoxicity, Neuromuscular blockade, Ototoxicity, Teratogen.

29

Aminoglycosides mnemonic

GNATS caNNOT kill anaerobes.

30

Tetracyclines (Tetracycline, doxycycline, minocycline) Mechanism

Bacteriostatic; bind to 30S, limited CNS penetration.

Doxycycline is fecally eliminated and can be used in patients with renal failure.

Do not take tetracyclines with milk, antacids or iron-containing preparations because divalent cations inhibit drugs’ absorption in the gut.

31

Tetracyclines (Tetracycline, doxycycline, minocycline) Clinical Use

Lyme Disease, M. pneumoniae, Rickettsia, Chlamydia, acne, vibrio cholera, brucellosis (unpasteurized cheese and milk)

demeclocycline used to treat SIADH

32

Tetracyclines (Tetracycline, doxycycline, minocycline) Toxicity

GI distress, discoloration of teeth and inhibition of bone growth in children, photosensitivity.

Fanconi-like syndrome - urine problems

Contraindicated in pregnancy.

33

Chloramphenicol mechanism

Blocks peptidyltransferase at 50S ribosomal subunit. Bacteriostatic.

34

Chloramphenicol clinical use

Meningitis and Rocky Mountain spotted fever (Rickettsia rickettsii)

35

Chloramphenicol toxicity

Anemia (dose dependent), aplastic anemia (dose independent), gray baby syndrome (in premature infants because they lack liver UDP-glucuronyl transferase).

36

Clindamycin mechanism

Blocks peptide transfer (translocation) at 50S ribosomal subunit. Bacteriostatic.

37

Clindamycin clinical use

Anaerobic infections in aspiration pneumonia, lung abscesses, and oral infections.

Also effective against invasive group A strep

38

Clindamycin use vs Metronidazole use

Treats anaerobic infections above the diaphragm vs. metronidazole (anaerobic infections below diaphragm).

39

Clindamycin toxicity

Pseudomembranous colitis (C. difficile overgrowth), fever, diarrhea.

40

Oxazolidinones (Linezolid) mechanism

Inhibit protein synthesis by binding to 50S subunit and preventing formation of the initiation complex.

41

Oxazolidinones (Linezolid) clinical use

Gram-positive species including MRSA and VRE

42

Oxazolidinones (Linezolid) toxicity

Bone marrow suppression (especially thrombocytopenia), peripheral neuropathy, serotonin syndrome.

43

Monobactams (Aztreonam) mechanism

Less susceptible to β-lactamases.
Prevents peptidoglycan cross-linking by binding to PBP-3.
Synergistic with aminoglycosides.
No cross-allergenicity with penicillins.

44

Monobactams (Aztreonam) clinical use

Gram-negative rods only

For penicillin-allergic patients and those with renal insufficiency who cannot tolerate aminoglycosides.

45

Monobactams (Aztreonam) toxicity

Usually nontoxic; occasional GI upset.

46

Macrolides (Azithromycin, clarithromycin, erythromycin) mechanism

Inhibit protein synthesis by blocking translocation (“macroslides”); bind to the 23S rRNA of the 50S ribosomal subunit.
Bacteriostatic.

47

Macrolides (Azithromycin, clarithromycin, erythromycin) clinical use

Atypicals

Atypical pneumonias (Mycoplasma, Chlamydia, Legionella), STIs (Chlamydia), gram-positive cocci (streptococcal infections in patients allergic to penicillin), and B. pertussis.

48

Macrolides (Azithromycin, clarithromycin, erythromycin) toxicity (MACRO mnemonic)

MACRO: Gastrointestinal Motility issues, Arrhythmia caused by prolonged QT interval, acute Cholestatic hepatitis, Rash, eOsinophilia.
Increases serum concentration of theophyllines, oral anticoagulants.
Clarithromycin and erythromycin inhibit cytochrome P-450.

49

Trimethoprim mechanism

Inhibits bacterial dihydrofolate reductase. block of folate synthesis.

Bacteriostatic.

50

Trimethoprim clinical use

Used in combination with sulfonamides (TMP- SMX)

Combination used for UTIs, Shigella, Salmonella, Pneumocystis jirovecii pneumonia treatment and prophylaxis, toxoplasmosis prophylaxis.

51

Trimethoprim toxicity (TMP mnemonic)

Megaloblastic anemia, leukopenia, granulocytopenia. (May alleviate with supplemental folinic acid).
TMP Treats Marrow Poorly.

52

Sulfonamides (Sulfamethoxazole (SMX), sulfisoxazole, sulfadiazine) mechanism

Inhibit folate synthesis. Para-aminobenzoic acid (PABA) antimetabolites inhibit dihydropteroate synthase. Bacteriostatic (bactericidal when combined with trimethoprim).
Dapsone, used to treat lepromatous leprosy, is a closely related drug that also inhibits folate synthesis.

53

Sulfonamides (Sulfamethoxazole (SMX), sulfisoxazole, sulfadiazine) clinical use

Gram-positives, gram-negatives, Nocardia, Chlamydia.

Triple sulfas or SMX for simple UTI.

54

Sulfonamides (Sulfamethoxazole (SMX), sulfisoxazole, sulfadiazine) toxicity

Hypersensitivity reactions, hemolysis if G6PD deficient, nephrotoxicity (tubulointerstitial nephritis), photosensitivity, kernicterus in infants
displace other drugs from albumin (e.g., warfarin).

55

Fluoroquinolones (Ciprofloxacin, norfloxacin, levofloxacin, ofloxacin, moxifloxacin, gemifloxacin, enoxacin) mechanism

Inhibit prokaryotic enzymes topoisomerase
II (DNA gyrase) and topoisomerase IV. Bactericidal.
Must not be taken with antacids.

56

Fluoroquinolones (Ciprofloxacin, norfloxacin, levofloxacin, ofloxacin, moxifloxacin, gemifloxacin, enoxacin) clinical use

Gram-negative rods of urinary and GI tracts (including Pseudomonas), Neisseria, some gram-positive organisms.

57

Fluoroquinolones (Ciprofloxacin, norfloxacin, levofloxacin, ofloxacin, moxifloxacin, gemifloxacin, enoxacin) toxicity

GI upset, superinfections, skin rashes, headache, dizziness. Less commonly, can cause leg cramps and myalgias.

Contraindicated in pregnant women, nursing mothers, and children 60 years old and in patients taking prednisone.

58

Fluroquinolones toxicity mnemonic

Fluoroquinolones hurt attachments to your bones.

59

Daptomycin mechanism

Lipopeptide that disrupts cell membrane of gram-positive cocci.

60

Daptomycin clinical use

S. aureus skin infections (especially MRSA), bacteremia, endocarditis, VRE.

Not used for pneumonia (avidly binds to and is inactivated by surfactant).

61

Daptomycin toxicity

Myopathy, rhabdomyolysis.

62

Metronidazole mechanism

Forms toxic free radical metabolites in the bacterial cell that damage DNA. Bactericidal, antiprotozoal.

63

Metronidazole clinical use (GET GAP on the Metro with metronidazole!)

Treats Giardia, Entamoeba, Trichomonas, Gardnerella vaginalis, Anaerobes (Bacteroides, C. difficile).

Used with a proton pump inhibitor and clarithromycin for “triple therapy” against H. Pylori.

64

Metronidazole toxicity

Disulfiram-like reaction with alcohol; headache, metallic taste.