Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PT > Bacterial Protein Synthesis Inhibitors > Flashcards

Bacterial Protein Synthesis Inhibitors Flashcards

1
Q

What is the MOA of tetracyclines?

A

Concentrate intracellularly in susceptible organisms
Drug binds reversibly to 30S subunit of bac ribosome -> prevents binding of tRNA to A site of mRNA-ribosome complex -> inhibit bac protein syn

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

What is the MOA of tigecycline?

A

Like minocycline, it binds to bac 30S ribosome, blocking entry of tRNA

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

What is the MOA of Aminoglycosides?

A

AGs bind to 30S sub, distorting subunit structure and causing misreading of mRNA

AGs transported across inner memb via active transport. Energy-dependent phase inhibited by anaerobic conditions, drop in pH and hyperosmolarity.

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

Absorption of Tetracyclines? Good or poor oral bioavailability?

A

Good oral F (adequately abs after oral ingestion)

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

Absorption of Tigecycline? Good or poor oral bioavailability?

A

IV, poor oral F

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

Absorption of AGs? Good or poor oral bioavailability?

A

Poor oral F; parenteral adm except neomycin (oral)

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

Elimination of Tetracycline

A

primarily eliminated by kidney

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

Elimination of Doxycycline

A

Doxycycline: bile and urine (hepatic)

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

Elimination of Minocycline

A

Minocycline: extensively metabolised by liver before excretion (hepatic)

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

Elimination of Tigecycline

A
  • Not extensively metabolised
  • Biliary/faecal
  • No dosage adjustments are necessary for pts w renal impairment
  • Dose reduction recommended in severe hepatic dysfn
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Excretion of AGs

A

Renal clearance. Dose adjustment needed w renal impairment.

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

Pregnancy Category for Tetracyclines

A

Cat D

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Pregnancy Category for Tigecycline

A

Cat D

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

Tetracycline is effective against which type of bacteria?

A

Activity against broad spectrum of Gram +ve/-ve, atypical bac and spirochete bacteria
Inadequate activity against Pseudomonas aeruginosa and Proteus

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

Tigecycline is effective against which type of bacteria?

A

Broad-spectrum activity:
 MRSA
 Multidrug-resistant (MDR) streptococci
 Vancomycin-resistant enterococci (VRE)
 useful against carbapenem resistant strains of Extended-spectrum β-lactamase (ESBL)–producing gram-negative bacteria
Not active against Pseudomonas species and Proteus

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

Glycylcycline designed to overcome what common mechanisms of tetracycline resistance? 2 of them

A
  • efflux pumps

- Ribosomal protection

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

AGs is effective against which type of bacteria?

A

aerobic Gram-ve bac
 Gram-ve infections; Enterobacteriaceae (Klebsiella, E.Coli), MDR microbes (Pseudomonas and Acinetobacter)
 2nd-line defence for MDR TB
 Empiric therapy for serious infection
 Once causative microbe is identified, AGs discontinued

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

Why is AGs combined with cell wall synthesis inhibitors?

A

 Expand empiric spectrum of activity of antimicrobial regimen to ensure presence of at least one drug active against a suspected pathogen
 Provide synergistic bacterial killings
 Prevent emergence of resistance to individual agents

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

Which tetracycline is used effectively against acne vulgaris and community-acquired pneumonia and skin and soft tissues caused by MRSA?

A

Doxycycline

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

Which AGs is the widest antimicrobial spectrum of AGs?

A

Amikacin

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

What is streptomycin primarily used for?

A

Primarily in combi w other antimicrobial agents in therapy of TB and other mycobacterial diseases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Neomycin is given oral administration for ____

A

bowel prep for surgery

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

Why is neomycin not given parenterally?

A

severe nephrotoxicity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Adverse effects of Tetra and Tige?

A
  • Gastric discomfort: (drink plenty of fluids and shouldn’t be taken immediately before going to bed) taken on EMPTY STOMACH
  • Effects on calcified tissues: discolouration & hypoplasia of teeth; temp growth stunt
  • Hepatotoxicity
  • Phototoxicity: severe sunburn
  • Vestibular dysfn: dizziness, vertigo, tinnitus
  • Renal side effects (less w doxycycline, more for tetracycline)
  • Superinfection: CDAD (observed >2 months post AB
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Contraindications for Tetra and Tige; not compatible for which age groups?

A
  • breast-feeding women;
  • children <8yo
  • Last half of pregnancy - affects primary teeth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are the 6NOs + other adv effects of AGs

A
  • No to Protein Synthesis (inhibition at 30S)
  • Mainly aerobic Gram-Negative Organisms
  • No to use during pregnancy; Cat D
  • No to oral adm
  • No to CSF penetration
  • Nephro and Oto toxicities
  • Neuromuscular paralysis (Myasthenia gravis): rapid inc conc or concurrent adm w neuromuscular blockers
  • Hypersensitivity reactions: skin rashs (esp for topically applied neomycin)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Why must we monitor the use of AGs?

A

• Caution for renal impairment

  • Myasthenia gravis
  • Avoid usage w other nephrotoxic drugs (Amp B, Vanco, NSAIDs, neuromuscular blocking agents
28
Q

Which factors predispose to Nephro and Ototoxicity for AGs?

A

 Dose
 Duration of treatment > 5 days
 Concomitant use of nephrotoxic drugs
 Age: elderly pts predisposed because of reduced renal fn
 Genetic predisposition (oto occurs in pts w point mutations in mit DNA)

29
Q

Why is there resistance of AGs?

A
  1. Inc efflux pumps red effective intracellular conc
  2. Gram -ve produce AG inactivating enzymes
  3. Some bac alter 30S, prevents AGs to interfere in protein syn
  4. Low level resistance may result from inhibition of AGs uptake by bacteria
30
Q

What is the MOA of Macrolides?

A

50s

• Inhibit translocation step: nascent peptide chain residing at the A site fails to move to the peptidyl donor (P) site

31
Q

What is the MOA of Clindamycin?

A

• Binds exclusively to 50S subunit of bac ribosome and inhibit peptide synthesis

32
Q

What happens when clindamycin is taken with erythromycin?

A

antagonise each other’s action –> cross resistance w macrolides due to (erm) methylases can also occur

33
Q

What is the MOA of Linezolid?

A

• Binds the bacterial 23S ribosomal RNA of the 50S subunit and prevents formation of functional 70S initiation complex (component of bacterial t/l process)

34
Q

Absorption of Macrolides; Good or poor F?

A

good oral F, poor CNS penetration

oral/IV; oral = clarithromycin

35
Q

Absorption of Clindamycin; Good or poor F?

A

 Excellent oral F; Oral and IV
 Available in topical soln, gel, lotion, vaginal cream
 Effective topically/orally for acne vulgaris and bacterial vaginosis

36
Q

Absorption of Linezolid; Good or poor F?

A

 Excellent oral F; well abs after oral adm and may be adm w/o regard to food
 Oral and IV

37
Q

Elimination of Macrolides? Both metabolism and excretion

A

 Erythro and Clarithro: Metabolised hepatically and excreted in bile and urine
 Azithro: Largely eliminated unchanged in faeces via biliary excretion

38
Q

Excretion of Clindamycin?

A

Mainly excreted as bioinactive metabolites

39
Q

Excretion of Linezolid?

A

Approx 80% of dose in urine

No dose adjustments required for renal/hepatic dysfn

40
Q

Why are there no dose adjustments required for renal/hepatic dysfn for Linezolid?

A

inactive metabolites - doesnt affect the dose

41
Q

Pregnancy Category for Macrolides

A

Category B (Erythro,Azithro); Category C (Clarithro)

42
Q

Pregnancy Category for Clindamycin

A

Category B

43
Q

Pregnancy Category for Linezolid

A

Category C

44
Q

Which 50S protein syn inhibitors are safe for pregnancy?

A

Macrolides, clindamycin save for pregnancy

45
Q

Which bacterial protein syn inhibitors target atypical bacteria?

A

Macrolides and Tetracyclines

46
Q

Which organisms does macrolides cover?

A

 Atypical microbes MCL (Legionella pneumophilia, Mycoplasma, Chlamydia)
 Resp tract infections (CAP), Chlamydial infections, Diphtheria, H. pylori (Clarithro/Azithro + ome + amox), Mycobacterial infections

47
Q

Which organisms does Clindamycin cover?

A

 Useful against Anaerobic infections
 Gram +ve; MRSA and streptococcus, penicillin resistant anaerobic bacteria
 Alternatives for pts w penicillin allergies
 Toxic shock syndrome (anti-toxigenic effect)
 For serious anaerobic infections
 Anaerobic infections of skin and soft tissues – Bacteriodes, Clostridium perfringen
 Good spectrum activity against oral pathogens
 Almost all aerobic Gram -ve bac are resistant. (Use AGs)

48
Q

Which organisms does Linezolid cover?

A

 Gram +ve: Staph, Strep, Enterococci, Listeria monocytogenes
 Not indicated for Gram-ve infections (resistant due to efflux pumps that force drug out of cell faster than it can accumulate)
 Penicillin resistant strains of S. pneumoniae, Vancomycin-intermediate
 MRSA , VRE (Vancomycin-resistant strains of enterococci), VRSA (Vancomycin-resistant strains of S. aureus)

49
Q

Which bacterial protein synthesis inhibitors is used as an alternative for pts w penicillin allergies?

A

Macrolides, Clindamycin

50
Q

Which drug is used for aerobic infections?

A

Aminoglycosides

51
Q

Which drug is used for anaerobic infections?

A

Clindamycin

52
Q

Which drugs only cover Gram +ve bacteria?

A

Linezolid, Vancomycin, Penicillinase Resistant Penicillin (Anti-staph)

53
Q

Which bacterial protein syn inhibitors cover MRSA?

A

Linezolid and clindamycin

tetracyclines and tigecycline

54
Q

Which macrolides is more active against resp infections, esp Community acquired pneumonia?

A

Azithromycin

55
Q

Which macrolides is a preferred therapy for STD caused by Chlamydia trachomatis and Neisseria gonorrhoea?

A

Azithromycin

56
Q

What does atypical bacteria consist of?

A

Mycoplasma, Chlamydia, Legionella

57
Q

Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella pneumophila are common causes of _________.

A

community-acquired pneumonia (CAP)

58
Q

Why must we be aware of the risk of Torsades de Pointes for macrolides?

A

May prolong QT interval; caution in pts w pro-arrhythmic conditions

59
Q

Which two drugs are required to drink a full glass of water and not to lie down immediately?

A

Clindamycin and tetracyclines

60
Q

Which 2 drugs’ adverse effects is CDAD?

A

Tetracyclines and Tigecycline

Clindamycin

61
Q

Why macrolides are contraindicated for pts w hepatic dysfn?

A

erythron and azithro accumulate in liver

 Erythro and Clarithro: Metabolised hepatically and excreted in bile and urine
 Azithro: Largely eliminated unchanged in faeces via biliary excretion

62
Q

Which drug has an adverse effect for pseudomembranous colitis ?

A

Tetra and Tige

63
Q

Which drug is contraindicated for pseudomembranous colitis ?

A

Clindamycin

64
Q

Which drug is used as a choice of ABx in macrolide resistant strains (efflux pumps)

A

Clindamycin

Clindamycin not a substrate for macrolide efflux pumps making them a choice of ABx in such macrolide resistant strains

65
Q

Number of days to cause BM suppression?

A

> 10 days of use

66
Q

Number of days to cause Irreversible peripheral neuropathies and optic neuritis

A

> 28 days of use

67
Q

in what ways can someone become resistant to clindamycin?

A

alter 50s or 23s

PT (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions