5- Antimicrobial Agents Flashcards

1
Q

Antibiotics acting through Inhibition of cell wall synthesis ?

A
Penicillins 
Cephalosporins 
Imipenem/Meropenem 
Aztreonam 
Vancomycin
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2
Q

Antibiotics acting through inhibition of bacterial protein synthesis ?

A
Aminoglycosides 
Chloramphenicol 
Macrolides 
Tetracyclines 
Streptogramines 
Linezolid 
Clindamycin
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3
Q

Antibiotics acting through inhibition of nucleic synthesis ?

A

Fluoroquinolones

Rifampin

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4
Q

Antibiotics acting through inhibition of folic acid synthesis ?

A

Sulfonamides
Trimethoprim
Pyrimethamine

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5
Q

Narrow spectrum penicillins ? Their spectrum ?

A

Penicillin G
Penicillin V

Streptococci
Pneumococci
Meningococci
Treponema pallidum

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6
Q

Very narrow spectrum penicillins ? Their spectrum ?

A

Nafcillin
Oxacillin
Methicillin

Staphylococci

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7
Q

Broad spectrum penicillins ? Their spectrum ?

A

Amoxicillin
Ampicillin

Both : gram +ve cocci except staph , E coli , H influenza
Ampicillin : listeria monocytogenes
Amoxicillin : borrelia , H pylori

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8
Q

Extended spectrum penicillins ? Their spectrum ?

A

Ticarcillin
Piperacillin

Increased activity against gram -ve rods including Pseudomonas

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9
Q

Examples for suicide inhibitors ?

A

Clavulanic acid

Sulbactam

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10
Q

Aminoglycosides with ticarcillin synergistic against ?

A

Pseudomonas

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11
Q

Aminoglycosides with amoxicillin synergistic against ?

A

Enterococcal species

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12
Q

Nafcillin and oxacillin eliminated largely in ?

A

Bile

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13
Q

Firist generation cephalosporins ? Their spectrum ? Use ?

A

Cefazolin
Cephalexin

Gram +ve cocci ( not MRSA )
E coli
Klebsiella pneumoniae
Some proteus species

In surgical prophylaxis

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14
Q

Second generation cephalosporins ? Their spectrum ?

A

Cefotetan
Cefaclor
Cefuroxime

Increased gram -ve coverage including some anaerobes

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15
Q

Third generation cephalosporins ? Their spectrum ? Use ?

A

Ceftriaxone IM
Cefotaxime parenteral
Cefdinir
Cefixime oral

Gram +ve and gram -ve cocci
Many gram -ve rods

Important in empiric management of meningitis and sepsis

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16
Q

Fourth generation cephalosporins? Spectrum ?

A

Cefepime IV

Wider than third generation

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17
Q

Organisms not covered by cephalosporins?

A
LAME 
Listeria monocytogenes 
Atypicals ( Chlamydia) 
MRSA
Enterococci
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18
Q

Tubular secretion of penicillins and cephalosporins is blocked by ?

A

Probenecid

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19
Q

In case of allergy to penicillins what drugs to choose to combat bacteria ?

A

For gram +ve organisms : Macrolides

For gram -ve rods : aztreonam

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20
Q

Imipenem and Meropenem spectrum ?

A

Gram +ve cocci
Gram -ve rods
Anaerobes

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21
Q

Imipenem is given with ? Why ?

A

Cilastatin

a renal dehydropeptidase inhibitor which inhibits imipenem metabolism to a nephrotoxic metabolite

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22
Q

Aztreonam spectrum ? Mode of administration ?

A

Gram -ve rods

IV

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23
Q

Vancomycin spectrum ?

A

MRSA
Enterococci
Clostridium difficile

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24
Q

Streptomycin is the DOC for ?

A

Bubonic plague

Tularemia

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25
Q

Antibiotics not used in pregnancy?

A

Aminoglycosides
Fluoroquinolones
Sulfonamides
Tetracyclines

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26
Q

Doxycycline is useful in ttt of ?

A

Prostatitis

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27
Q

Minocyclin is used in ?

A

Meningococcal carrier state

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28
Q

Tigecyclin is used in ?

A

Complicated skin , soft tissue and intestinal infections

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29
Q

Antibiotics that causes phototoxicity ?

A

Tetracyclines
Sulfonamides
Quinolones

30
Q

Chloramphenicol is metabolized by ?

A

Hepatic glucuronidation

31
Q

Macrolides spectrum ?

A
Gram +ve cocci 
Atypical organisms 
Legionella pneumophila 
Campylobacter jejuni
Helicobacter pylori 
Mycobacterium avium intracellulare
32
Q

Telithromycin ?

A

A ketolide active against macrolide resistant S. Pneumonia

33
Q

Clindamycin spectrum ?

A

Gram +ve

Anaerobes

34
Q

Clindamycin side effect ?

A

Pseudomembranous colitis

35
Q

Linezolid uses ?

A

Ttt of :
VRSA
VRE
Drug resistant pneumococci

36
Q

Side effects of linezolid ?

A

Bone marrow suppression

MOA-a and b inhibitor

37
Q

Streptogramins ?

A

Dalfopristin

Quinupristin

38
Q

Spectrum of streptogramins ?

A

VRSA
VRE
Drug resistant gram +ve cocci

39
Q

Sulfonamides inhibit ?

A

Dihydropteroate synthase

40
Q

Inhibitors of dihydrofolate reductase ?

A

Trimethoprim

Pyrimethamine

41
Q

DOC in Nocardia ?

A

Cotrimoxazole

42
Q

Sulfonamides are metabolized by ?

A

Hepatic acetylation

43
Q

Mechanism of action of Amphotericin B and nystatin ? Their uses ?

A

Interact with ergosterol in fungal membranes to form artificial pores which disrupts membrane permeability

Amphotericin B : DOC for severe infections caused by cryptococcus and mucor

Nystatin : used topically for localized infections ( candidiasis )

44
Q

Mechanism of action of Azoles ?

A

Inhibit 14-alpha demethylase

45
Q

Itraconazole is DOC for ?

A

Blastomycoses
Sporotrichoses
Aspergillosis

46
Q

Flucytosine mechanism of action ?

A

Activated by fungal cytosine deaminase to 5-fluorouracil which after triphosphorylation is incorporated into fungal RNA
5-FU also forms 5-fluorodeoxyuridine monophosphate which inhibits thymidylate synthase

47
Q

Mechanism of action of Acyclovir ?

A

Monophosphorylated by viral thymidine kinase to acyclovir triphosphate which is both a substrate for and inhibitor of viral DNA polymerase
When incorporated into the DNA molecule acts as a chain terminator

48
Q

Ganciclovir uses ? Side effects ?

A

Mostly used in prophylaxis and ttt of CMV infections including retinitis in AIDS and transplant patients

Hematotoxicity
Mucositis 
Fever 
Rash 
Crystalluria
49
Q

Foscarnet side effects ?

A

Nephrotoxicity with acute tubular necrosis , electrolyte imbalance with hypocalcemia

50
Q

Side effects of Zidovudine?

A

Hematotoxicity
Myopathy
Peripheral neuropathy

51
Q

Side effects of Didanosine ?

A

Pancreatitis
Peripheral neuropathy
Hyperuricemia
Liver dysfunction

52
Q

Side effect of protease inhibitors ?

A

Metabolic syndrome

53
Q

Side effect of Ritonavir ?

A

Induces CYP 1A2 and inhibit the major P450 isoforms ( 3A4 , 2D6 )

54
Q

Integrase inhibitor ?

A

Raltegravir

55
Q

Fusion inhibitors ?

A

Enfuvirtide

Maraviroc

56
Q

MOA of Enfuvirtide?

A

Binds to gp41 and inhibits the fusion HIV-1 to CD4+ cells

57
Q

MOA of Maraviroc ?

A

Blocks the binding of the gp120 HIV protein to CCR5 on macrophage surface to prevent viral entry

58
Q

MOA of Zanamivir and Oseltamivir ?

A

Inhibit neuraminidases of influenza A and B —> decreases the likelihood that the virus will penetrate uninfected cells

59
Q

Ribavorin MOA ?

A

Monophosphorylated form inhibits IMP dehydrogenase

Triphosphorylated form inhibits viral RNA polymerase and end-capping of viral RNA

60
Q

Uses of Ribavirin ?

A

Adjunct to alpha interferons in hepatitis C
Respiratory syncytial virus
Lassa fever
Hantavirus

61
Q

Side effects of Ribavirin ?

A

Hematotoxic
Upper airway irritation
Teratogenic

62
Q

Sofosbuvir MOA ?

A

Nucleotide analog that inhibits RNA polymerase

63
Q

Simeprevir MOA ?

A

Hepatitis C protease inhibitor

64
Q

Ledipasvir MOA ? Combined with ?

A

Inhibits HCV NS5A protein that play a key role in RNA replication
Combined with Sofosbuvir

65
Q

DOC for lechmaniasis ?

A

Stibogluconate

66
Q

DOC for Trypanosomiasis ?

A

Chagas disease : Nifurtimox

African : Arsenicals

67
Q

Side effects of metronidazole ?

A

Metallic taste

Disulfiram like action

68
Q

Ttt of malaria in chloroquine resistant regions ?

A

Quinine +- ( doxycycline or clindamycin or pyrimethamine)

69
Q

MOA of albendazole ?

A

Decrease glucose uptake

Decrease microtubular structure

70
Q

MOA of praziquantel?

A

Increase Ca influx

Increase vacuolization