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Flashcards in Antimicrobials Deck (107)
1

MOA of penicillin

- bind penicillin binding proteins (transpeptidases) and block transpeptidase cross-linking of peptidoglycan

- activate autolytic enzymes

2

Penicillinase resistant penicillins

- Oxacillin, nafcillin, dicloxacillin

- use for S. aureus (except MRSA)

3

Aminopenicillins

- Ampicillin, amoxicillin

- combine with clavulanic acid to protect against beta-lactamase

4

Beta lactam antipesudomonals

- Ticarcillin, piperacillin

5

Beta-lactamase inhibitors

- CAST
- Clavulanic Acid, Sulbactam, Tazobactam

6

MOA of cephalosporins

- beta lactams that inhibit cell wall synthesis but are LESS susceptible to penicillinases

7

Organisms not covered by cephalosporins

- LAME
- Listeria, Atypicals (Chlamydia, Mycoplasma), MRSA, and Enterococci

8

Indications for 1st generation cephalosporins (cefazolin, cephalexin)

- gram positive cocci and PEcK
- Proteus, E. coli, Klebsiella

- cefazolin used prior to surgery to prevent S. aureus infections

9

Indications for 2nd generation cephalosporins (cefoxitin, cefaclor, cefuroxime)

- gram positive cocci and HEN PEcKS
- Haemophilius, Enterobacter, Neisseria, Proteus, E. coli, Klebsiella, Serratia

10

Indications for 3rd generation cephalosporins (ceftriaxone, cefotaxime, ceftazidime)

- serious gram negative infections resistant to other beta-lactams

- ceftriaxone: meningitis and gonorrhea
- ceftazidine: pseudomonas

11

Indications for 4th generation cephalosporins (cefepime)

- increased activity against pseudomonas and gram positive organisms

12

MOA of aztreonam

- monobactam resistant to beta-lactamases
- prevents peptidoglycan cross-linking by binding to PBP3
- synergistic with aminogycosides

13

Indications for aztreonam

- gram negative rods only
- penicillin allergic pts.
- pts. with renal insufficiency who cannot tolerate aminoglycosides

14

MOA of imipenem/cilastatin

- beta-lactamse resistant carbapenem
- always given with cilastatin (inhibitor of renal dehydropeptidase I) to decrease inactivation of drug in renal tubules

15

MOA of vancomycin

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

- Bactericidal

16

Indications for vancomycin

- gram positive only: MRSA, enterococci, and C. difficile

17

Toxicity of vancomycin

- nephrotoxicity, ototoxicity, thrombophlebitis

- Red Man Syndrome: diffuse flushing (can be prevented by pretreatment with antihistamines and slow infusion rate)

18

Resistance to vancomycin

- amino acid change of D-ala D-ala to D-ala D-lac

19

Protein synthesis inhibitors

- Buy AT 30, CCEL at 50

- 30S inhibitors: aminoglycosides (bactericidal) and tetracyclines (bacteriostatic)

- 50S inhibitors: chloramphenicol, clindamycin (bacteriostatic), erythromycin (macrolide, bacteriostatic), and linezolid (variable)

20

MOA of aminoglycosides

- gentamicin, neomycin, amikacin, tobramycin, streptomycin
- bactericidal
- inhibit formation of initiation complex and cause misreading of mRNA
- also block translocation

21

Indications for aminoglycosides

- severe gram negative rod infections
- synergistic with beta-lactams

- ineffective against anaerobes because they require O2 for uptake

22

Toxicity of aminoglycosides

- nephrotoxicity (esp. when used with cephalosporins)
- ototoxicity (esp. when used with loop diuretics)
- neuromuscular blockade
- teratogen

23

Mechanism of resistance against aminoglycosides

- transferase enzymes that inactivate the drug by acetylation, phosphorylation or adenylation

24

MOA of tetracyclines

- tetracycline, doxycycline, demeclocycline, minocycline
- bacteriostatic
- bind to 30S and prevent attachment of aminoacyl-tRNA

- divalent cations inhibit its absorption in the gut (don't take with milk, antacids, or iron-containing solutions)

25

5 indications of tetracyclines

- Borrelia burgdorferi
- M. pneumonia
- Rickettsia
- Chlamydia
- demeclocyline is also an ADH antagonist and used as a diuretic in SIADH

26

Toxicity of tetracyclines

- discoloration of teeth and inhibition of bone growth in children
- C.I. in pregnancy

27

Mechanism of resistance against tetracylines

- decreased uptake or increased efflux via transport pumps
- chemical modification and ribosomal protection

28

MOA of macrolides

- azithromycin, clarithromycin, erythromycin
- bacteriostatic
- block translocation by binding to the 23S rRNA of the 50S ribosomal subunit

29

Indications for macrolides

- atypical pneumonia
- STDs (Chlamydia)
- gram positive cocci

30

Toxicity of macrolides

- MACRO
- motility issues, arrhythmia, acute cholestatic hepatitis, rash, eosinophilia

- increases serum concentrations of theophyllines, oral anticoagulants (warfarin)

31

Mechanism of resistance against macrolides

- methylation of 23S rRNA binding site

32

MOA and indications of chloramphenicol

- MOA: blocks peptidyltransferase at 50S ribosomal subunit, bacteriostatic

- indication: meningitis (H. influenza, N. meningitidis, S. pneumoniae)

33

MOA and indications of clindamycin

- MOA: blocks peptide transfer (transpeptidation) at 50S ribosomal subunit, bacteriostatic

- indication: anaerobic infections (above the diaphragm compared to metronidazole which treats anaerobic infections below the diaphragm)

34

MOA of sulfonamides

- PABA antimetabolites inhibit dihydropteroate synthase
- bacteriostatic

35

Mechanism of resistance to sulfonamides

- altered enzyme (bacterial dihydropteroate synthase), decreased uptake, or increased PABA synthesis

36

MOA of trimethoprim

- inhibits bacterial dihydrofolate reductase
- bacteriostatic

37

Toxicity of trimethoprim and what drug can help prevent toxicity

- megaloblastic anemia, leukopenia, and granulocytopenia

- leucovorin is used for folinic acid rescue

38

MOA of fluoroquinolones

- inhibits DNA gyrase (topoisomerase II) and topoisomerase IV
- bactericidal
- topoisomerase II: more effective in gram negatives
- topoisomerase IV: more effective in gram positives

39

Toxicity of fluoroquinolones

- tendon rupture, prolonged QT interval
- C.I. during pregnancy

- must not be taken with antacids

40

MOA of metronidazole

- forms free radical toxic metabolites in the bacterial cell that damage DNA
- bactericidal, antiprotozoal

41

Indications for metronidazole

- GET GAP
- Giardia, Entamoeba, Trichomonas, Gardnerella, Anaerobes (Bacteroides, C. difficile), H. pylori

42

4 drug regimen of TB treatment

- RIPE
- rifampin, isoniazid, pyrazinamide, ethambutol

43

MOA and toxicity of isoniazid

- MOA: decreased synthesis of mycolic acid, requires catalase peroxidase (KatG) to convert to active metabolite

- toxicity; neurotoxicity, hepatotoxicity
- Pyridoxine (vit. B6) can prevent neurotoxicity

44

MOA and toxicity of rifampin

- MOA: inhibits DNA-dependent RNA polymerase

- toxicity: orange colored urine

45

MOA of toxicity of ethambutol

- MOA: decreased carbohydrate polymerization of mycobacterium cell wall by blocking arabinosyltranferase

- toxicity: optic neuropathy (red-green colorblindness), decreased visual acuity, and central scotomas

46

Treatment of MRSA and VRE

- MRSA: vancomycin

- VRE: linezolid and streptogramins (quinupristin/dalfopristin)

47

MOA of amphotericin B

- binds ergosteraol and forms membrane pores that allow leakage of electrolytes

48

Indication for nystatin

- oral candidiasis (thrush), diaper rash or vaginal candidiasis

49

MOA of azoles

- inhibit fungal sterol (ergosterol) synthesis by inhibiting the P-450 enzyme that converts lanosterol to ergosterol

50

Indications of azoles

- cryptococcal meningitis in AIDS pts and candidal infections of all types

51

MOA of terbinafine

- inhibits the fungal enzyme squalene epoxidase

52

MOA of griseofulvin

- interferes with microtubule function, disrupts mitosis

53

Indication of nifurtimox

- T. cruzi

54

Indication of chloroquine

- plasmodial species other than P. falciparum

55

Treatment of flukes (trematodes)

- praziquantel

56

MOA and indications of zanamivir and oseltamivir

- MOA: inhibit influenza neuraminidase, decreasing the release of progeny virus

- indications: influenza A and B

57

MOA and indications of ribavirin

- MOA: inhibits synthesis of guanine nucleotides by competitively inhibiting IMP dehydrogenase

- indications: RSV, chronic hepatitis C

58

MOA of acyclovir

- activated by thymidine kinase and acts as a guanosine analog

- preferentially inhibits viral DNA polymerase by chain termination

59

Indications of acyclovir

- HSV and VZV

60

MOA and indication of ganciclovir

- MOA: guanosine analog, preferentially inhibits viral DNA polymerase

- indication: CMV

61

MOA and indication of foscarnet

- MOA: viral DNA polymerase inhibitor that binds to the pyrophosphate binding site of the enzyme, does not require activation by viral kinase

- indication: CMV retinitis

62

MOA and indication of cidofovir

- MOA: preferentially inhibits viral DNA polymerase, does not require phosphorylation by viral kinase

- indication: CMV retinitis

63

MOA of interferons

- block replication of both RNA and DNA viruses

64

Indications for IFN-alpha, beta and gamma

- IFN-a: chronic HBV and HBC, Kaposi's sarcoma

- IFN-b: MS

- IFN-g: NADPH oxidase deficiency (chronic granulomatous disease)

65

Cephalosporin that covers MRSA

- ceftaroline

66

Side effects of cephalosporins

- vitamin K deficiency
- increases nephrotoxicity of aminoglycosides

67

Side effects of cloramphenicol

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

68

Side effect of clindamycin

- pseudomembranous colitis (C. difficile)

69

Indications for rifampin other than TB

- meningococcal prophylaxis and chemoprophylaxis in contacts of children with H. influenza type B

70

MOA of pyrazinamide

- acidify intracellular environment
- effective in acidic pH of phagolysosomes

71

Treatment of M. avium

- azithromycin, rifampin, ethambutol, and streptomycin

72

Treatment of M. leprae

- dapsone and rifampin for tuberculoid form

- add clofazimine for lepromatous form

73

Prophylaxis against TB

- isoniazid

74

Prophylaxis against M. avium

- azithromycin

75

Prophylaxis for meningococcal infection

- ciprofloxacin (DOC), rifampin for children

76

Prophylaxis for gonorrhea

- ceftriaxone

77

Prophylaxis for syphillis

- benzathine penicillin G

78

Prophylaxis for history of recurrent UTIs

- TMP-SMX

79

Prophylaxis for endocarditis with surgical or dental procedures

- penicillins

80

Prophylaxis for pregnant women carrying group B strep

- ampicillin

81

Prophylaxis for strep pharyngitis in children with prior rheumatic fever

- oral penicillin

82

Prophylaxis for prevention of post-surgical infection due to S. aureus

- cefazolin

83

Prophylaxis for prevention of gonococcal or chlamydial conjunctivitis in newbron

- erythromycin ointment

84

HIV prophylaxis for CD4 < 200

- TMP-SMX to protect against PCP

85

HIV prophylaxis for CD4 < 100

- TMP-SMX to protect against PCP and toxo

86

HIV prophylaxis for CD4 < 50

- azithromycin to protect against M. avium

87

Antifungals that alter membrane function

- amphotericin B and nystatin

88

Antifungals that alter cell wall synthesis

- caspofungin and anidulfungin

89

Antifungals that alter nucleic acid synthesis

- 5-flucytosine

90

Antifungals that alter lanosterol synthesis

- naftifine and terbinafine

91

Antifungals that alter ergosterol synthesis

- "azoles"

92

MOA of flucytosine

- inhibits DNA and RNA biosynthesis by conversion to 5-fluorouracil by cytosine deaminase

93

MOA of caspofungin, micafungin

- inhibits cell wall synthesis by inhibiting synthesis of beta-glucan

94

MOA of chloroquine

- blocks detoxification of heme into hemozoin, heme accumulates and is toxic to plasmodia

95

Indication for pyrimethamine

- toxoplasmosis

96

Indication for suramin and melarsoprol

- T. brucei

97

Indication for sodium stibogluconate

- Lesihmaniasis

98

Indication for praziquantel

- flukes (nematodes) such as Schistosoma

99

Side effect of acyclovir

- nephrotoxicity
- prevent with aggressive hydration

100

Adverse effect of sulfonamides during pregnancy

- kernicterus

101

Adverse effect of aminoglycosides during pregnancy

- ototoxicity

102

Adverse effect of fluoroquinolones during pregnancy

- cartilage damage

103

Adverse effect of clarithromycin during pregnancy

- embryotoxic

104

Adverse effect of tetracyclines during pregnancy

- discolored teeth, inhibition of bone growth

105

Adverse effect of ribavirin during pregnancy

- teratogenic

106

Adverse effect of griseofulvin during pregnancy

- teratogenic

107

Adverse effect of cloramphenicol during pregnancy

- gray baby syndrome