Flashcards in aminoglycosides Deck (42)
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1
Some drugs and aminoglycosides
• As the plasma level is increased above the MIC, the drug kills an increasing proportion of bacteria at a more rapid rate
conc dependent
2
Any antibiotic, including penicillins and cephalosporins
• Directly related to time above MIC
• Independent of concentration once the MIC is reached
TIME DEPENDENT
3
Structurally related amino sugars attached by glycosidic linkages
aminoglycosides
4
are aminoglycosides polar or not
polar
5
RoA of aminoglycosides
Given intramuscularly or intravenously for systemic effects
6
Are aminoglycosides absorbed orally?
no
7
tissue penetration of aminoglycosides (full partial limited)
Limited
8
Does it readily cross the blood-brain barrier
no
9
Major mode of excretion
•
Glomerular filtration
10
Excretion is directly proportional to ---- clearance
creatinine
11
With normal renal function, elimination half-life is
2-3 h
12
Peak serum levels
Measured at
30-60 minutes after administration
13
Trough serum levels
Measured when
just before the next dose
14
MoA of AG
Bactericidal (irreversible) inhibitors of protein synthesis
15
Penetration of bacterial cell wall is partly dependent on ___________
O2-dependent active transport
16
Transport is enhanced by ________
cell wall synthesis inhibitors
17
Bind to _____ AND Interfere with protein synthesis
30S ribosomal unit
18
ag interfere with protein synthesis by
1. Block formation of initiation complex
2. Cause misreading of the code on the mRNA template
3. Inhibit translocation
19
MECHANISMS OF RESISTANCE
Failure to penetrate into the cell
Plasmid-mediated formation of inactivating enzymes
20
• Primary mechanism of resistance
Plasmid-mediated formation of inactivating enzymes
21
•
Catalyze the acetylation of amine functions
Transfer of phosphoryl or adenyl groups to the O2 atoms of hydroxyl groups on the aminoglycoside
Group transferases
22
transferases produced by enzyme can inactivate
• Amikacin
• Gentamicin
• Tobramycin
• Not streptomycin
• Netilmicin is less susceptible and is active against more strains of organisms
23
for Serious infections caused by aerobic gram (-) bacteria
• E. coli Enterobacter
• Klebsiella Proteus
• Providencia Pseudomonas
• Serratia
GENTAMICIN, TOBRAMYCIN, and AMIKACIN
24
Tuberculosis
Plague
Tularemia
Multi-drug-resistant (MDR) strains of M. tb resistant to streptomycin maybe susceptible to amikacin
STREPTOMYCIN
25
Used topically
Locally
• In the GIT
• Eliminate bacterial flora
NEOMYCIN
26
Reserved for serious infections resistant to other aminoglycosides
NETILMICIN
27
Aminocylitol related to aminoglycosides
Back-up drug
Intramuscular as single dose for gonorrhea
SPECTINOMYCIN
28
A. OTOTOXICITY
Auditory or vestibular damage (or both) maybe irreversible or reversible?
IRREVERSIBLE
29
DRUGS RESPONSIBLE FOR
• Auditory impairment
Amikacin and kanamycin
30