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Flashcards in Antibiotics II Deck (48)
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1

Tetracyclines

(Protein Synthesis Inhibitors)

DOXYCYCLINE
Tetracycline
Minocycline
Tigecycline

2

Aminoglycosides

(Protein Synthesis Inhibitors)

GENTAMYCIN
TOBRAMYCIN
Amikan
Streptomycin

3

Cloramphenicol

category?

(Protein Synthesis Inhibitors)

4

Antifolates

(DNA Synthesis Inhibitors)

SULFAMETHOXAZOLE (SMX)
TRIMETHOPRIM / SMX (Cotrimoxazole)
Dapsone

5

Fluoroquinolones

(DNA Synthesis Inhibitors)

CIPROFLOXACIN
LEVOFLOXACIN
MOXIFLOXACIN
Ofloxacin

6

(Urinary Tract Antisceptics)

Nitrofurantoin
Methenamine

7

How to initiate protein synthesis?

f-met tRNA = binds initiation factors and 30s + 50s

8

Protein synthesis inhibitors - 30s inhibitor

Buy AT 30, CCELL at 50.

Aminoglycosides [-cidal]
Tetracyclines [-static]

9

Protein synthesis inhibitors - 50s inhibitor

Buy AT 30, CCELL at 50.

Chloramphenicol, Clinda [-static]
Erythromycin [-static]
Lincomycin [-static]
Linezolid [variable]

10

Tetracyclines

[-static}
characteristics

*bacteria selective (no euk)
*binds reversibly to 30S
*blocks binding of amino-tRNA to A site
(can't add aminos)
*gram +/-

11

Tetracyclines

resistance

*efflux (use DOXY, mino, tige)
*30S ribosome protection (use tige)
*Enzymatic inactivation (acetylation)
TIGECYCLINE -no cross resistance

12

Doxycycline PO/IV
Minocycline

(Tetracyclines)

low renal clearance
longer t1/2

13

Tigecycline IV

(Tetracyclines)

*glycylcycline
*MDR organisms - MRSA, VRE, ESBL

14

Doxycycline

(Tetracyclines)
use

atypical pneumonia
NGU (chlamydia)
Rocky Mtn. Spotted Fever
Lyme Disease

15

Tetracyclines

[-static}
ADME

*Ca, Mg, Fe, Al, food, divalent metals - down absorption
*bones/teeth
*Minocycline - CSF
*non-renal elimination = Mino/doxy/Tige (SAFEST FOR kidney problems)

16

Tetracyclines

[-static}
Toxicities

*gut microflora change
*superinfection
*Mino/doxy - vestibular dysfunction (up CNS penetration)
*Outdated - renal tubular acidosis (fanconi syndrome)
*grey teeth - no kids under 8 + pregger

17

Aminoglycosides

Mnemonic

Mean GNATS can NOT kill anaerobes

amino-, genta/neo/amikan/tobra/strepto
Nephro/oto-toxic, teratogen
need O2 - inner membrane transport

18

Aminoglycosides

MOA

*binds 30s
*slows proof-reading
*more bacterial membrane permiability
*OUT by kidney

19

Aminoglycosides

resistance

***Enzymatic inactivation
*Impaired uptake
*ribosomal protein mutation (strepto)

20

Aminoglycosides

efficacy

*-cidal
*irreversible
*works hours after cleared
*concentration-dependent killing
LOWER TOXICITY - 1x day (larger dose)

21

Aminoglycoside

Specificity

*Aerobic Gram -ve enteric
(pseudomonas)
*Genta/Tobra - all Gram -, Pseudomonas (more tobra)

22

Aminoglycosides

synergy

+ B-lactam/vanc
*thinner cell wall, more penetration
+ Pen/Vanc
*wall inhibitor (ALWAYS), more Rx in periplasmic space

23

Aminoglycosides

ADME

*doesn't cross membrane, stays in plasma (use- sepsis!) + B lactam = up tissue levels
*NO ORAL, use iv/im
*Tobra - nebulized (Pseudomonas - cystic fibrosis)

24

Aminoglycosides:

Toxicities

*oto/nephro-toxic
(renal impairment - monitor plasma after 3 doses)
*irreversible
*Vestibular damage

25

Chloramphenicol

MOA

*Binds 50s
*stops peptidyltransferase
*can affect eukaryotic ribosomes (stop aerobic metabolism)

26

Chloramphenicol

ADME

*Liver metab
*Cyp 2C/3A inhibition
*caution-infants/alcoholics (bad liver)

27

Chloramphenicol

Toxicities

Hematological Effects:
• Bone marrow suppression
• Aplastic anemia
DON'T USE
• “Gray Baby Syndrome”
• Potential for Drug Interactions:

28

Antifolates (TMP/SMX) block

folate synthesis of Nucleic Acids

29

SMX targets

(Antifolates)

PABA , block folate production (bacteria only--mammals have dietary folate)
*dihydropteroate synthase

30

TMP targets

(Antifolates)

Folate (bacteria + humans)
*Dihydrofolate Reductase
-bacteria selective - HUGE dose needed for human