Aminoglycosides, tetracyclines, flagyl, bactrim and tigecycline

Question 1

Aminoglycoside options

Answer 1

Gentamysin, tobramycin, amikacin, streptomycin, neomycin

Question 2

MOA of aminoglycosides

Answer 2

actively transported across cytoplasmic membranes into the interior of the bacterial cell, requires energy, o2 and a higher pH, bind to 30S ribosome inhibiting protein synthesis

Question 3

PK of aminoglycosides

Answer 3

bactericidal activity, and concentration dependent, IV only, also IM, IT, intraventricullarly, inhaled and topical, 100% renaly eliminated, wt based dosing

Question 4

Spectrum of activity of aminoglycosides

Answer 4

aerobic, gram negative rods, enterobacteriaceae, S. Aureus- not monotherapy

Question 5

What is generally considered best option for GNR?

Answer 5

tobramycin

Question 6

In what bacteria is gentamycin used for synergistic purposes?

Answer 6

S. Aureus

Question 7

What is reserved for tobramycin and gentamycin resistant?

Answer 7

amikacin

Question 8

Clinical use of aminoglycosides?

Answer 8

only use monotherapy for UTI, gram- sepsis, HCAP, bacteremia, gram+ synergy

Question 9

What should aminoglycosides not be used for?

Answer 9

skin infections

Question 10

ADRs of nephrotoxicity

Answer 10

Nephrotoxic and ototoxic; usually develops 5-7 days after therapy, generally milk AKI and reversible

Question 11

What does it mean if a pt develops drop in creatinine after start of aminoglycoside therapy

Answer 11

It may just be to course of disease— not therapy, because it takes 5-7 days for there to be negative affect on kidneys from the therapy

Question 12

Trimethoprim/Sulfamethoxazole (Bactrim) typical form?

Answer 12

used as double strength, 1 tab PO BID, 400, 800 mg

Question 13

MOA of bactrim?

Answer 13

inhibits sequential steps in folate synthesis of susceptible organisms, bacteriostatic when alone, but combined is bactericidal

Question 14

Spectrum of bactrim?

Answer 14

aerobic gram+, staph (MRSA and MSSA, CA not HA), strep- resistance increasing, listeria monocytogenes, nocardia- DOC, Aerobic gram -, e.bacteriaceae- resistance inc, M. catarrhalis, H. influenza, s.maltophilia, b. cepacia, p. jiroveci

Question 15

What is Bactrim DOC for?

Answer 15

nocardia, burkholderia cepacia, pneumocystis jiroveci

Question 16

What does bactrim not cover?

Answer 16

pseudomonas

Question 17

Bactrim PK?

Answer 17

IV and PO, renally eliminated, DI w/ warfarin (should dec warfarin dose by 50%)

Question 18

when on bactrim IV, what should be done?

Answer 18

concurrent fluid administration- 2 L/day

Question 19

ADRs of Bactrim?

Answer 19

N/V/D, anorexia, hematologic, hyperkalemia

Question 20

Clinical use of bactrim

Answer 20

CA- MRSA SSTI, UTI- resistance worsening, PSP p. jiroveci, nocardia infections DOC- requires very high dose, pyelonephritis, prostatitis

Question 21

What is bactrim DOC for?

Answer 21

nocardia infections with high doses, and PCP P. jiroveci

Question 22

What are the tetracyclines?

Answer 22

doxycycline (Vibramycin), ,tetracycline, minocycline (Minocin)

Question 23

What is the dose of doxycycline?

Answer 23

100 mg PO BID

Question 24

MOA of tetracyclines?

Answer 24

binds to 30 s ribosome to inhibit RNA-dependent protein synthesis, bacteriostatic

Question 25

Spectrum of tetracyclines?

Answer 25

gram +, staph, strep- not PCN resistant, e.bacteriaceae, h. influenzae, m. catarrhalis, tick bourne disease, acne vulgaris and borrelia burgdorferi

Question 26

What is doxycylcine for?

Answer 26

CA-MRSA, and rickettsia

Question 27

What is doxycycline and minocycline used for?

Answer 27

all the atypicals, legionella, mycoplasma pneu, chlamydophilia pneu

Question 28

What forms of tetracyclines are available?

Answer 28

All po, doxy and minocycline are available IV

Question 29

ADRs of tetracyclines?

Answer 29

N/V/D, photosensitivity, dec oral contraceptives, discoloration of teeth, dec bone development

Question 30

Clinical use of tetracycline?

Answer 30

CA-MRSA- doxy, chlamydia, lyme disease, PID-Doxy, rocky mountain spotted fever, acne- minocycline, atypical infections

Question 31

Tigecycline (Tygacil) MOA

Answer 31

a glycylcycline, inhibits protein synthesis, bacteriostatic, IV only

Question 32

Spectrum of activity of tigecylcine?

Answer 32

aerobic Gram +, MSSA, MRSA, strep- multidrug resistant s. pneu, enterococci- VRE, very broad spectrum gram -, drug resistant e. bacteriaceae, carbapenem resistant, anaerobes, atypicals, good for abd infections

Question 33

What is tigecycline not good for?

Answer 33

proteus or pseudomonas

Question 34

Tigecycline (Tygacil) clinical use

Answer 34

complicated SSTI, intra-abd, culture proven pan-resistant pathogens

Question 35

ADRs of tigecycline (Tygacil)

Answer 35

N/V/D- significant, use cautiously if tetracycline allergy, photosensitivity, discoloration of teeth

Question 36

Metronidazole (Flagyl) MOA

Answer 36

binds to and disrupts DNA and nucleic acid synthesis, bactericidal, conc dependent

Question 37

Dose of flagyl

Answer 37

500 mg PO/IV TID-QID

Question 38

Spectrum of activity of flagyl

Answer 38

only anaerobic , gram -: bacteroides, fusobacterium, prevotella, C. dif, trichomonas vaginalis, giardia lamblia

Question 39

Flagyl adrs

Answer 39

N/V/D, metallic taste, pancreatitis, CNS complications, disulfiram rxns- avoid w/ EtOH

Question 40

What should be done if people on flagyl develop CNS sx

Answer 40

must d/c therapy, seen w/ large doses or prolonged therapy, peripheral neuropathy, , seizures, confusion, ataxia, vertigo

Question 41

Flagyl Clincial use

Answer 41

first line option for c. diff, add on therapy for other abd infxns- diverticulitis etc, bacterial vaginosis, STD, “below diaphragm”