Infectious diseases: Pharmacology - Antimicrobial summary

Question 1

Aminoglycosides

Answer 1

Irreversibly inhibits 30S subunit
O2 dependent transport into cell
Gentamicin, streptomycin, amikacin, tobramycin
Aerobic Gram negatives

Question 2

Macrolides

Answer 2

Reversibly inhibits 50S subunit
Erythromycin, clarithromycin, azithromycin
Corynebacteria, Chlamydia, CAP (atypical cover)

Question 3

Lincosamides

Answer 3

Reversibly inhibits 50S subunit
Clindamycin
Toxic shock (inhibits GAS toxin production), skin and soft tissue infection

Question 4

Nitroimidazole

Answer 4

Reactive reduction species
Metronidazole
Anaerobes, cerebral abscess (crosses BBB)

Question 5

Sulfonamides

Answer 5

Competes with PABA in folic acid synthesis
Sulfamethoxazole, sulfadiazine

Question 6

Pyrimidine

Answer 6

Inhibits bacterial dihydrofolate reductase
Trimethoprim

Question 7

Quinolones

Answer 7

DNA gyrase inhibitors
Moxifloxacin, ciprofloxacin, norfloxacin
Gram negatives (moxi Gram positive), Pseudomonas (cipro), anthrax

Question 8

Chloramphenicol

Answer 8

Reversibly binds 50S subunit
Broad-spectrum

Question 9

Tetracyclines

Answer 9

Reversibly inhibits 30S subunit
Doxycycline, tetracycline
Mycoplasma pneumoniae, Chlamydia, Rickettsiae, NOT gonococcal (resistance)

Question 10

Resistance mechanism of MRSA, pneumococci, enterococci

Answer 10

Modification of target PBPs

Question 11

Natural penicillins

Answer 11

Penicillin G (benzylpenicillin), penicillin V (phenoxymethylpenicillin)
Gram positives, Gram negative COCCI only, non B-lactamase producing anaerobes

Question 12

Anti-staphylococcal penicillins

Answer 12

Methicillin, dicloxacillin, flucloxacillin
Staphylococci, streptococci
B-lactamase resistant

Question 13

Extended spectrum penicillins

Answer 13

Ampicillin/amoxicillin, piperacillin, ticarcillin
Gram positives and Gram negatives, antipseudomonal (except amp/amoxi)

Question 14

First generation cephalosporins

Answer 14

Cephalexin
Cephazolin
Cephalothin

Question 15

Second generation cephalosporins

Answer 15

Cefotetan*
Cefaclor
Cefuroxime
Cefoxitin

• anaerobic cover

Question 16

Third generation cephalosporins

Answer 16

Ceftriaxone
Cefotaxime
Ceftazidime*

• Pseudomonas cover

Question 17

Fourth generation cephalosporin

Answer 17

Cefipime*

• Pseudomonas, penicillin-resistant Streptococci, and Enterobacter cover

Question 18

Which cephalosporin can cause hypoprothrombinaemia?

Answer 18

Cefotetan

Question 19

Which cephalosporin can have a disulfaram-like effect?

Answer 19

Cefotetan

Question 20

Cross-reactivity cephalosporins with penicillins
Cross-reactivity carbapenems with penicillins

Answer 20

Cephalosporins: 5-10%
Carbapenems: 1%

Question 21

Carbapenems

Answer 21

Beta lactam
Meropenem, imipenem, ertapenem
GNRs including Pseudomonas (except erta)
Multi-resistant organisms and mixed infections

Question 22

Vancomycin

Answer 22

Glycopeptide antibiotic, binds terminus of peptidoglycan to inhibit elongation and cross-linking
MRSA, C. diff colitis (given oral - poor absorption)

Question 23

Antimycobacterials

Answer 23

Isoniazid
Rifampin
Pyrazinamide
Ethambutol

Question 24

Isoniazid

Answer 24

Inhibits mycolic acid synthesis

Question 25

Rifampin

Answer 25

Inhibits DNA-dependent RNA polymerase

Question 26

Amphotericin B

Answer 26

Binds ergosterol, creates pores in fungal cell membrane

Question 27

Azoles

Answer 27

Inhibits fungal cytochrome P450
Fluconazole, ketoconazole

Question 28

Acyclovir, famciclovir, valcyclovir

Answer 28

HSV and VZV
Inhibit viral DNA polymerase
Activated by virus-specified thymidine kinase

Question 29

Ganciclovir, valganciclovir

Answer 29

CMV
Inhibit viral DNA polymerase and terminates chain

Question 30

Foscarnet

Answer 30

CMV
Inhibits herpesvirus DNA polymerase/RNA polymerase, HIV reverse transcriptase

Question 31

NRTIs

Answer 31

Nucleoside reverse transcriptase inhibitors:
- Zidovudine (AZT)
- 3TC
- Abacavir
- Tenofovir

Question 32

NNRTIs

Answer 32

Non-nucleoside reverse transcriptase inhibitors:
- Nevirapine
- Delavirdine

Question 33

Protease inhibitors

Answer 33

“Avir”s: atazanavir, darunavir, ritonavir

Question 34

Oseltamivir

Answer 34

Neuraminidase inhibitor

Question 35

Amantadine, rimantadine

Answer 35

Inhibit influenza viral uncoating

Question 36

Palivizumab

Answer 36

RSV monoclonal antibody

Question 37

Pre-exposure prophylaxis

Answer 37

NRTI (tenofovir + emtricitabine)

Question 38

CLEan TAg

Answer 38

50S subunit: chloramphenicol, lincosamide (clindamycin), erythromycin (macrolides)

30S subunit: tetracyclines, aminoglycosides