Protein Synthesis Inhibitors Flashcards

(61 cards)

1
Q

What do the protein synthesis inhibitors act on?

A

30S, 50S Ribosomal subunits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What class of drugs are used against 30S?

A

Tetracyclines, glycylcycline, aminoglcosides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does tetracycline work?

A

Tetracyclines concentrate intracellularly and bind irreversibly to 30S subunit of bacteria ribosome, prevent binding of tRNA to the A site of the mRNA-ribosome complex, thus inhibiting protein synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What to avoid when taking tetracyclines?

A

Food(best on empty stomach)
Dairy products containing calcium –> decrease absorption and F

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Can pregnant women take tetracyclines?

A

No.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does tetracyclines bind to during distribution?

A

Tissues undergoing calcification
(Bones/teeth)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How is CSF penetration for tetracyclines?

A

Moderate
(More for mino and doxycycline)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Can tetracyclines be taken with beta-lactams?

A

No. Avoid administering both

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Is tetracyclines effectuve against Pseudomonas?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Which tetracyclines be used against MRSA?

A

Doxycycline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How are tetracyclines administered?

A

Orally

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does tetracycline cover?

A

Gram negative and positive(MRSA)
- Rickettsia
- Chlamydia
- Mycoplasma
- Vibrio cholerae
- Yersinia Pestis

  • S pneumoniae
  • Bacillus anthracis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What can treat acne too?

A

Doxycycline,minocycline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How are the tetracyclines excreted?

A

Tetracycline: R
Doxycycline: unchanged in bile n urine
Minocycline: Liver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Name a glycylcycline

A

Tigecycline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Why are glycylcycline developed?

A

Overcome resistance from efflux pumps and/or ribosomal protection with a stringer affinity to active site of 30S, blocking entry of transfer RNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How is tigecycline administered?

A

IV, poor oral F

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Is it good for bloodstream infections?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How is tigecycline excreted

A

Bile/fecal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

When is dose adjustment for tigecycline needed?

A

Hepatic impairment, no need for renal impairment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is tigecycline used for?

A
  1. MRSA
  2. multi-drug resistant streptococci
  3. Vancomycin-resistant enterococci (VRE)
  4. Extended spectrum beta-lactamase(ESBL) gram negative bacteria, resistant to carbepenem
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Can tigecycline be used against Pseudomonas?

A

No.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

ADR of tigecycline

A
  1. GI discomfort (take on empty stomach)
  2. Discolouration of teeth stunt growth
  3. Hepatotoxicity
  4. Phototoxicity (use sunscreen)
  5. Vestibular dysfunction: dizzyness, vertigo, tinnitus more for minocycline.
  6. Renal SE
  7. Superinfection for prolonged use (CDAD >2m)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

CI of tetracyclines/tigecycline

A

Pregnant women, children <8yo
Oral Sulfonylurea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
How does aminoglycosides work?
Aminoglycoside diffuse through aqueous porin channels for gram-negative bacteria and transport across inner membrane via active transport(can be inhibited by anaerobic conditions, drop in pH and hyperosmolarit) Aminoglycosides distorts ribosome structure by binding to them and 1. blocking formation of initiation complex 2. Causing misreading of codons as wrong amino acyl tRNA are able to bind to A site without matching codon present in mRNA in that position 3. Inhibit translocation
26
Aminoglycosides has a synergistic effect with _____________ against ___________ though they work primarily against ______
Cell wall synthesis inhibitors Gram positive bacteria Aerobic gram negative bacteria and mycobacteria
27
Aminoglycosides has a _______-dependent killing
Concentration
28
Administration of aminoglycosides
Mainly Parenteral (except neomycin), poor oral F due to polar
29
Can Aminoglycosides be used for CSF infections?
No
30
Excretion of aminoglycosides
Renal
31
Name 5 aminoglycosides
1. Gentamicin 2. Tobramycin 3. Amikacin 4. Streptomycin 5. Neomycin
32
What does aminoglycosides cover?
Gram negatives - Klebsiella - Escherichia coli - Pseudomonas - Acinetobacter - 2nd line for tuberculosis
33
What has the widest range among aminoglycosides?
Amikacin IM/IV/IT
34
______ is used with _____ to treat enterobacteriaceae (Klebsiella, Proteus) + enterococcal endocarditis
Gentamicin/streptomycin Penicillin/ceftriaxone
35
What aminoglycoside can be used against Pseudomonas?
Tobramycin, Amikacin
36
Which aminoglycosides is most toxic?
Neomycin (oral and topical)
37
What is applied topically for bowel prep for surgery?
Neomycin
38
CI for neomycin
Intestinal obstruction, gastric/ intestinal ulcer, hx of Aminoglycoside hypersensitivity
39
Excretion for aminoglycosides
Renal except neomycin(faeces)
40
What is amikacin ineffective against?
Anaerobic gram positive strains
41
What is streptomycin ineffective against?
Aerobic GNR
42
ADR of Aminoglycosides
1. Ototoxicity 2. Nephrotoxicity 3. Neuromuscular paralysis 4. Hypersensitivity rxns: rash, contact Dermatitis 5. CI: Pregnancy, <8yo
43
Monitoring for aminoglycosides
Renal, hearing, myasthenia gravis - avoid use with other nephrotoxic drugs (Amphotericin B, Vancomycin, NSAIDs and neuromuscular blocking agents) - TDM, RFT (Urea, creatinine, electrolytes)
44
6 amiNOglycosides
NO protein synthesis mainly aerobic gram Negative Organisms NO use in pregnancy NO oral administration NO CSF pentration Nephro and Ototoxicity
45
Factors tt predispose to Nephro/ototoxicity
1. Dose 2. Duration >5d 3. Concomitant nephrotoxic drugs 4. Age (renal function) 5. Genetic
46
Mechanisms of resistance against aminoglycosides
1. Increased efflux pumps 2. Aminoglycoside inactivating enzyme production 3. Altered 30S 4. Inhibition of Aminoglycoside uptake
47
What classes of drugs are used for protein synthesis inhibition of 50S?
Macrolides Lincosamide - Clindamycin Oxazolidinones - Linezolid
48
Macrolides MOA
inhibit 50S ribosomal subunit, inhibiting translocation step such that peptide chain is unable to move to P site
49
Name 3 macrolides
1. Erythromycin 2. Clarithromycin 3. Azithromycin
50
Cns penetration of macrolides?
Poor
51
Macrolides are effective against?
Atypicals, Substitute for penicillin allergy
52
Mocrolide clearance
Ec - hepatic A - biliary,excretion, unchanged in faeces
53
ADR of macrolides
1. GI 2. Hepatotoxicity 3. Ototoxicity 4. QTc prolongation 5. ddi - cyp450 inhibitor
54
Clindamycin MOA
Binds to 50s subunit, inhibit p synthesis, Antagonistic effect with macrolides (cross resistance)
55
Clindamycin is effective against?
MRSA Streptococcus PR anaerobic bacteria (bacteroides, clostridioides perfringen)
56
Entry into CNS for clindamycin
Poor
57
ADR clindamycin
1. Esophageal irritation - take with a glass of water 2. GI DV 3. CDAD
58
Resistance to clindamycin
Altered 50s by aa substitution Alterations in 23s by methylation and nucleotidylation of hydroxyl grp of clindamycin
59
Linezolid covers?
Gram positive bacteria
60
Moa of linezolid
Binds to 23s ribosomal rna of 50s and prevents 70s initiation complex
61
Cautions in linezolid
DNU within 2w of MAOI Avoid tyrosine containing food and serotonergic drugs --> hypertensive crisis