AntibacterialAntibioticsC

Question 1

A drug may be static or cidal depending on what factors?

Answer 1

Concentration of drug, site of infection, and infecting organism

Question 2

What is the aminoglycoside spectrum of activity?

Answer 2

Active against aerobic gram ñ bacilli, usually used in combo with other agents, exhibits concentration-dependent killing and have a pronounced post- antibiotic effect

Question 3

What are the most widely used aminoglycosides?

Answer 3

Gentamicin, tobramycin, amikacin

Question 4

Which drugs related to aminoglycosides are used to tx gonorrhea in pts with PCN allergies?

Answer 4

Streptomycin

Question 5

What are the ADRs of aminoglycosides

Answer 5

Ototoxicity- may be reversible, Nephrotoxicity- - usually reversible, Avoid in sulfite allergies

Question 6

Can aminoglycosides be orally absorbed?

Answer 6

No

Question 7

What are the gentomicin dosing strategies?

Answer 7

Once daily- recommended 5-7mg/kg daily, Multiple daily: synergy dose- load 3mg/kg then 1mg/kg Q 8hrs maintenance

Question 8

What are aminoglycoside drug interactions?

Answer 8

Increased nephrotoxicity w/ loop diuretics, Resp depression when given w/ non depolarizing muscle relaxants, Neomycin affects digoxin levels- alters GI flora for metabolism

Question 9

What are category D aminoglycosides for special populations?

Answer 9

Amikacin, streptomycin, tobramycin, kanamycin, 8th cranial nerve toxicity in fetus

Question 10

What are category C aminoglycosides for special populations?

Answer 10

Gentamicin, neomycin- minimal absorption PO

Question 11

What is another special population for aminoglycosides?

Answer 11

Breastfeeding- AAP compatible

Question 12

What are the 3 groups of tetracyclines based on PK traits?

Answer 12

Short-acting- oxytetracycline, tetracycline, Intermediate- acting- demeclocycline (no longer an antibiotic), Long-acting- preferred, doxycycline and minocycline

Question 13

What is the MOA for tetracyclines?

Answer 13

Inhibits protein synthesis, reversibly binds to 30S subunit of RNA, Bacteriostatic

Question 14

What is the most important mechanism of resistance?

Answer 14

Bacterial efflux pump

Question 15

What are the most common ADRs of tetrcayclines?

Answer 15

N,V,D

Question 16

What rxn is limited to minocycline use?

Answer 16

Vestibular, lupus like rxn

Question 17

How are tetracyclines eliminated?

Answer 17

Mostly kidneys

Question 18

What is the 3rd generation TCN and what is it indicated for?

Answer 18

Tigecycline, Tx : complicated intraabdominal infections, complicated skin infections

Question 19

What drug is reserved for life threatening infections like typhoid and why?

Answer 19

Chloramphenicol, Bc it can cause blood dyscrasias

Question 20

What 2 populations should chloramphenicol NEVER be used in?

Answer 20

Pregnant women and neonates

Question 21

What are the macrolides and their MOA?

Answer 21

Erythromycin, clanthromycin, azithromycin, Inhibit protein synthesis, bacteriostatic at low doses but bactericidal at high concentrations

Question 22

What is the spectrum of activity for macrolides?

Answer 22

Erythromycin: gram + bacteria and spirochets ( legionella, N.gonorrheae, n. meningitidis, h influenzae), Clarithromycin and Azithromycin: gram + and anaerobic (h influenzae, h pylori, mycobacterium avium, )

Question 23

Which macrolide is H. influenzae resistant?

Answer 23

Erythromycin

Question 24

What are the ADRs of erythromycin?

Answer 24

GI- N/V/D most common. Some CV, cholestatic jaundice

Question 25

Why is erythromycin administered as enteric coated tablet or capsule?

Answer 25

Base is destroyed in the stomach acid

Question 26

What are drug interactions for macrolides?

Answer 26

CYP3A4(erythro/ clarithro) Lots of interactions

Question 27

Is azithromycin metabolized by the CYP3A4?

Answer 27

NO

Question 28

What are ketolides and what organisms do they have activity against?

Answer 28

New macrolide, semi-synthetic derivative of erythro, Increased activity against gram + and macrolide resistant strains

Question 29

What is telithromycin indicated for?

Answer 29

CAP, sinusitis, bronchitis

Question 30

What is the black box for telithromycin?

Answer 30

Liver failure, death, risk of ventricular arrhythmias, contraindication for MG

Question 31

What is the spectrum of activity for clindamycin and what is its most important indication?

Answer 31

Gram +, and anerobes , Most important indication for tx of anaerobic or mixed infections

Question 32

What is the topical indication for clindamycin?

Answer 32

acne

Question 33

Clindamycin is the most common antibiotic to cause what?

Answer 33

C diff

Question 34

What are the indications of Quinupristin- dalfopristin?

Answer 34

Life threatening infections associated with vanco-resistant bacteremia ( VRE)

Question 35

What are the oxazolidinones and their indications?

Answer 35

Linezolid and tedizoid, VRE/MRSA

Question 36

When is linezoid a bacteriostatic? Cidal?

Answer 36

Static: enterococci/staph, Cidal: strep

Question 37

What do you need to be concerned for when prescribing tedizoid

Answer 37

C diff

Question 38

What is the tRNA inhibitor and its indications?

Answer 38

Mupirocin, Topical skin tx- like impetigo. ( bactroban)