Antibiotics III: Inhibitors of Protein Synthesis

Question 1

Macrolide drug

Answer 1

Azithromycin (Z-pak)

Question 2

Macrolides are bacteriocidal/bacteriostatic

Answer 2

Bacteriostatic (can become bactericidal at high concentrations)

Question 3

Macrolides are excreted ____

Answer 3

In bile/feces

Question 4

Macrolides are _____ inhibitors

Answer 4

CYP3A4

Question 5

Adverse reactions of Macrolides

Answer 5

GI irritation
Hepatotoxicity
Prolonged Q-T interval

Question 6

Lincosamide drug

Answer 6

Clindamycin

Question 7

Clindamycin MOA

Answer 7

Binds 50S to block peptide bond formation
Bacteriostatic

Question 8

Clindamycin penetrates well into ____ and ____

Answer 8

Bone; abscessed tissue

Question 9

Boxed warming of Clindamycin

Answer 9

C. diff colitis/diarrhea

Question 10

Oxazolidinone drug

Answer 10

Linezolid

Question 11

Linezolid MOA

Answer 11

Binds to 23S rRNA of 50S subunit to block formation of initiation complex

Question 12

Linezolid can be used to treat drug-resistant infections but is limited by its ______

Answer 12

Toxicity

Question 13

Adverse effects of Linezolid

Answer 13

Myelosuppression (check CBC weekly)
Neuropathy
Lactic acidosis

Question 14

Boxed warning for Linezolid

Answer 14

Inhibits MAO; avoid use with antidepressants
Can cause lethal serotonin syndrome

Question 15

Inhibition of ribosomal function is bacteriostatic, not bacteriocidal, except for which protein synthesis inhibitor class?

Answer 15

Aminoglycosides (cause mRNA miscoding)

Question 16

Why do protein synthesis inhibitors have selective toxicity?

Answer 16

They bind with higher affinity to bacterial 70S ribosomes than mammalian 80S ribosomes

Question 17

Aminoglycoside drug

Answer 17

Gentamicin

Question 18

Aminoglycosides are highly polar and positive/negative charged

Answer 18

Positive

Question 19

Aminoglycosides are bacteri____ and active against G_ bacilli

Answer 19

Bactericidal
Aerobic G- bacilli

Question 20

Aminoglycosides reach cytosol of bacteria by ____ and ____

Answer 20

Filtration through porins
O2 dependent transport across membrane

Question 21

Post-antibiotic effect

Answer 21

Residual activity after drug falls below MIC

Question 22

Most antibiotics should be dosed according to ___ body weight

Answer 22

Ideal (doesn’t distribute through fat well)

Question 23

Gentamicin adverse effects

Answer 23

Nephrotoxicity
Ototoxicity (tinnitus and hearing loss)

Question 24

Is it better to give one large dose of gentamicin or 3 smaller doses per day?

Answer 24

1 large dose (longer “washout” time limits ototoxicity)

Question 25

Tetracycline drug

Answer 25

Doxycycline

Question 26

Doxycycline MOA

Answer 26

Actively transported into bacterial cells; binds to 30S ribosomal subunit and prevents addition of amino acids

Question 27

Tetracyclines are very broad/narrow spectrum

Answer 27

Broad (includes tick-born illnesses and malaria)

Question 28

Tetracycline drug interactions

Answer 28

Dairy
Iron supplements
Mg-laxatives
Antacids

Question 29

Tetracycline adverse reactions

Answer 29

GI upset
Photosensitivity
Deposits into developing bone and teeth (discoloration)

Question 30

All tetracyclines except ___ should be avoided in pregnant people and children <8

Answer 30

Doxycycline