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D&D Infectious Disease Midterm > Pharm - Aminoglycosides, Mupirocin, and Retapamulin > Flashcards

Pharm - Aminoglycosides, Mupirocin, and Retapamulin Flashcards

1
Q

name 8 aminoglycosides

A

amikacin
gentamicin
tobramycin
neomycin
streptomycin
kanamycin
sisomycin
netilmicin

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2
Q

briefly explain MOA of aminoglycosides

A

irreversibly bind 30s subunit

bactericidal concentration dependent

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3
Q

are streptomycins used orally?

explain why or why not

A

not used orally

have R-O-R glycosidic bond - will be hydrolyzed rapidly

really only used topically or IV

also very polar so not the best distribution

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4
Q

is treptomycin more active at alkaline or acidic pH?

A

alkaline

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5
Q

which aminoglycoside is least likely to be resistant? why?

A

amikacin

has a very large R group. other aminoglycosides can get modified at 5 positions, but aminoglycoside can only get altered at 1 position (#1 position)

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6
Q

which enzymes are capable of inactivating aminoglycosides at 5 different places

A

transferases

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7
Q

name 4 MOAS of aminoglycosides

A
  1. block initiation of protein synthesis
  2. block further translation and initiate premature termination - forms short proteins
  3. incorporate the incorrect amino acid
  4. breakup polysomes into monosomes (streptosomes)
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8
Q

which bacteria are aminoglycosides MOST active against

A

aerobic gram (-) bacteria

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9
Q

what are “streptosomes”

A

ribosomes that have aminoglycoside antibiotics bound to them

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10
Q

do aminoglycosides have gram (+) action?

A

their main action is against aerobic gram negative

that said, they are a little bit active against (+), but beta lactams are much better choices

if beta lactams and aminoglycosides used together - gives synergy!!!

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11
Q

which particular subunit do aminoglycosides bind

reversibly or irreversibly?

A

16s subunit of 30s ribosome

once bound - DOES NOT COME OFF - irreversible

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12
Q

true or false

aminoglycosides are bactericidal and irreversible protein synthesis inhibitors

A

TRUE

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13
Q

how do aminoglycosides enter the bacteria

A

through porin channels - energy dependent

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14
Q

TRUE OR FALSE

aminoglycosides do not have postantibiotic effect

A

FALSE - they fo

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15
Q

as mentioned, aminoglycosides are irreversible and bactericidal

are they conc or time dependent

A

concentration dependent

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16
Q

3 resistance mechanisms to aminoglycosides

which is MAJOR clinically

A

MAJOR - production of transferase enzyme that inactivates the aminoglycoside

  1. impair entry into cell – gram (-) decrease their porins
  2. receptor protein on 30s ribosomal subunit may be mutated
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17
Q

as mentioned, the major resistance mechanism against aminoglycosides is the production of transferase enzymes that inactivate the aminoglycoside antibiotic

name 3 enzymatic methods of this inactivation

A

AMPylation
acetylation
phosphorylation

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18
Q

aside from giving synergy, what is an advantage of administering a beta lactam with an aminoglycoside

A

will decrease the chance of developing resistance

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19
Q

how are aminoglycosides administered and why

A

IM/IV - NOT ORAL - bc poor oral absorption -highly polar so distribution not good

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20
Q

true or false

aminoglycosides have high distribution in the brain and CSF

A

FALSE - very low

bc so polar

21
Q

if aminoglycosides need to reach high levels in the brain or CSF, what is done?

A

intrathecal/itnraventricular injection

however this is not rly done bc so painful — usually will use something else

22
Q

explain the 2 alternative dosing of aminoglycosides

A

traditionally it’s 2-3 times a day

can give a high dose QD – this gives concentration dependent killing and post antibiotic effect

23
Q

how are aminoglycosides excreted and why important

A

RENALLY

need to consider creatinine clearance when dosing

24
Q

which 4 aminoglycosides have the widest spectrum

A

amikacin
tobramycin
gentamicin
netilmicin

25
Q

true or false

aminoglycosides are not active against gram (+) MSSA

A

false - they are, it’s just not that good agaisnt it

beta lactams preferred

26
Q

true or false

aminoglycosides are not active against anaerobic bacteria

A

TRUE

really only best against aerobic gram (-)

27
Q

using aminoglycosides with ________ gives synergy

A

beta lactams

28
Q

aminoglycosides are used almost exclusively for what

A

serious and life threatening NOSOCOMIAL infections

29
Q

aminoglycosides can be used topically for what

A

ocular (eye) and external ear infections

30
Q

3 main toxicities of aminoglycosides

A

ototoxicity

nephrotoxicity

potentiation of neuromuscular blockade

31
Q

explain the ototoxicity of aminoglycosides

A

can cause hearing loss as well as vestubular damage (affects balance)

32
Q

which 3 aminoglycosides are the most ototoxic?

which 2 are the most vestibulotoxic?

A

ototoxic – neomycin, kanamycin, amikacin

vestibular - streptomycin, gentamicin

33
Q

which 3 aminoglycosides are the most nephrotoxic

A

neomycin
tobramycin
gentamicin

34
Q

aside from aminoglycosides, what other antibiotics can potentiate the neuromuscular blockade

A

tetracyclines and clindamycin

35
Q

are aminoglycosides used in pregancy

A

NO - because of all the AE

36
Q

recap - which subunit do aminoglycosides bind and how do they bind

A

irreversibly bind 30s

37
Q

true or false

aminoglycosides are not potent against gram (-) aerobes

A

FALSE - they are

38
Q

mupirocin is for _______ use only

A

topical

39
Q

MOA mupirocin

A

inhibits protein synthesis by reversibly binding and inhibiting isoleucyl tRNA synthase

without isoleucine - can’t synthesize proper proteins

40
Q

is mupirocin static or cidal

against what bacteria

A

cidal against MANY (+) and select (-)

41
Q

resistance mechanism to mupirocin

A

mutated isoleucyl tRNA synthase (plasmid-mediated)

42
Q

name some specific clinical uses for mupirocin

A

-traumatic skin lesions and IMPETIGO infected with staph aureus or strep pyogenes

-nose ointment to eradicate staph aureus nasal carriage

43
Q

AE of mupirocin

A

not a lot - it’s topical

but can cause irritation and sensitivity at application site

44
Q

what is retapamulin used for

A

like mupirocin - an ointment for impetigo

45
Q

MOA of retapamulin

A

binds unique site on 50s subunit
selectively inhibiting protein synthesis

46
Q

retapamulin is a semisynthetic ______ derivative

A

pleromutilin

47
Q

retapamulin is effective in the treatment of uncomplicated……. caused by……

A

superficial skin infections caused by groups A and B hemolytic streptococci and staph aureus (NOT MRSA)

48
Q
A

D&D Infectious Disease Midterm (26 decks)

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