Brainscape's Knowledge GenomeTM

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


See full index

anti bacterial drugs > Protein synthesis inhibitors > Flashcards

Protein synthesis inhibitors Flashcards

1
Q

Discuss the characteristics of tetracycline

A
  • Bacteriostatic

* Basic structure and activity is common

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

Give the important examples of tetracycline

A
  1. doxycycline

2. minocycline

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

Discuss the spectrum of tetracycline

A

They have abroad spectrum

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

What are the uses of tetracycline

A
  • Chronic bronchitis
  • Tigecycline is used in tetracycline resistant bacteria
  • DRUG OF CHOICE AGAINST ORGANISM ;
  • Rickettsia
  • chlamydia
  • brucellosis
  • Mycoplasma
  • spirochaetal infections
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Discuss the mechanism of action of tetracycline

A
  • Enter microbe via passive diffusion and active transport in gram pos cells .
  • sensitive cells concentrate the drug intracellularly
  • Then binds to 30S bacterial ribosomal subunit
  • Then prevents formation of initial complex
  • Inhibits codon -anti codon interaction ultimately preventing insertion of new codon

Tetracyclines are crystalline amphoteric molecules(has acid and base properties ) and thus has low soluability

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

What can lead to resistance of tetracycline

A
  1. Decaresed intracellular accumulation(decreased influx or active efflux)
  2. Production of protein that interferes with the binding of tetracycline on ribosome
  3. Enzymatic inactivation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Discuss the pharmacodynamics of tetracycline

A
  • Orally administered and must be taken with adequate fluid
  • Antacids or milk prevent absorption because they form insoluble complexes
  • Tetracycline are widely distributed eg they can cross the placenta and enter breast milk
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Discuss the pharmacokinetics of doxycycline and minocycline particularly

A
  • highly lipid soluble
  • Nearly completely absorbed in the presence of food
  • they are less incline to chelate
  • They are mainly excreted in bile and safer in renal impairment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the side effects of tetracyclines ?

A
  1. Cause GIT disruption eg nausea and vomiting (dose related )
  2. Destruction of gut flora due to irritation of mucous membrane resulting superinfections with candida
  3. Pseudomembraneous colitis due clostridium difficile can also occur ( due to the antibacterial effect on gut flora )
  4. Causes hepatotoxic effects in elderly patients
  5. leads to photosensitivity
  6. Deposited in bone and teeth
  7. cause bone retardation in children
  8. Discolouration of nails and teeth
  9. Potentially nephrotoxic
  10. Reduced efficacy in combined oral contraceptive pill
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the side effects of minocycline

A
  • Blue-grey pigmentation of the skin and pigmentation of acne scare
  • vestibular toxicity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are side effects of tigecycline

A

increased mortality and treatment failure noted

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

how does tetracycline?

A
  1. Carbamazepine ,phenytoin ,barbiturates ,rifampicin (serum levels of doxycycline decreased )
  2. Vitam A and other retinoids enhances risk of increased intracranial pressure
  3. Combined oral contraceptive pill
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Discuss the cautions / contraindication

A
  1. Systemic lupus erythematosus
  2. Myasthenia gravis
  3. Heptic impairment
  4. porphyria
  5. elderly
  6. C/I in pregnancy ,children more than 8-12 years
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Discuss the chloramphenicol

A
  • Bacteriostatic
  • Broad spectrum antibiotic
  • RARELY USED AS FIRSST CHOICE TREATMENT BECAUSE OF POTENTIALLY TOXICITY
  • Only reserved for severe infections by susceptible organisms due to potential to cause aplastic anemia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Discuss the spectrum and uses of chloramphenicol

A

Used for

  • rickettsia infections and meningitis
  • typhoid fever
  • Used for bacterial eye infection
  • Must not be used for long term treatment
  • nor for prophylactic uses
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Discuss the spectrum of chloramphenicol

A
  • Chlamydia and mycoplasma infections
  • strep and staph cocci
  • hemophilic infections
  • anaerobes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Discuss the MOA of chloramphenicol

A
  1. Powerful inhibitors of protein synthesis
  2. Attaches to 50S ribosomal subunit
  3. Interferes with the MOA of peptidyltransferase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How can resistance be gain against chloramphenicol

A

1.Production of chloramphenicol acetyltransferase that inactivates the drug

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

Discuss the pharmacokinetics of chloramphenicol

A
  • Highly soluble in water
  • when orally digested it give 80% bioavailability
  • It is widely distributed and occurs in high levels in brain and CFS
  • 30-50% is protein bound
  • half life is 1.5 - 4 hours ( It is prolonged i young children )
  • It is metabolized in the liver after glucuronide formation ,it is excreted in the urine
20
Q

What are the side effects of cloramphenicol -7

A
  • Irreversible bone depression resulting in aplastic anemia ( bad for cancer patients )
  • Dose-related reversible bone marrow toxicity
  • efficacy is reduced when combined with contraceptive pill
  • use with great care in babies ,because of ineffective conjugation with glucuronic acid ,the drug is not excreted leading to grey baby syndrome
  • grey baby syndrome symptoms : abdominal distention ,cyanosis ,vasomotor collapse and failure to feed
  • GIT effects ,optic and peripheral neuritis
  • Hypersensitivity reaction and jaundice
  • inhibits liver enzymes
21
Q

How does chloramphenicol interact with other drugs ?

A
  1. Causes hepatic enzyme inhibition thus increase concentrations of phenytoin ,warfarin
  2. Used with hepatic enzymes inducers ,resulting in efficacy of chloramphenicol
  3. When combined with vit b ,folic acid and iron ,it may interfere with homological response
  4. Combined with oral contraceptive pill
22
Q

What are the Cautions/Contraindication of chloramphenicol

A 
C/I :
– Allergy
– Porphyria
– Third trimester of pregnancy
– Neonates
– Lactation
Caution:
– Impaired hepatic function
– Bone marrow depression
23
Q

Discuss the characteristics of clindamycin

A
  • attacks susceptible gram pos infections in patients with allergic to penicillin
  • Sensitive staphylococcal and anaerobic infections
  • Used for severe soft tissue infections
  • lung abscesses
  • quinsy
  • inactive against enterococci
  • bacteriostatic but bactericidal at high concentrations
24
Q

Clindamycin MOA

A
  • Similar mechanism to action of macrolides and the binding site is similar to macrolides
  • It inhibits the 50S subunit of bacterial ribosomes
  • interferes with formation of initial complex
  • inhibits translocation
25
Q

How can resistance be developed against clindamycin

A
  • Mutation of binding site

* Enzymatic inactivation

26
Q

Discuss the pharmacokinetics of clindamycin

A
  • Can be well absorbed with oral ,IM or IV administration
  • Must be taken with enough water
  • Widely distributed except for CSF
  • half life is 2-3 hrs and it is prolonged in hepatic and renal diseased patients
  • it is excreted in bile
  • 10% in urine
27
Q

Discuss the side effects of clindamycin - 5

A
  • Diarrhea ,nausea and skin reaction
  • Transient increase in liver enzymes and bilirubin
  • temporary leucopenia ,thrombocytopenia ,eosinophilia
  • Pseudomembranous colitis : caused by clostridium difficile
  • Affected by contraceptive pill
28
Q

How does clindamycin interact with other drugs

A

Oral contraceptive

29
Q

Cautions in clindamycin

A

1.GIT disease
*severe hepatic impairment
*porphyria
elderly
pregnancy / lactation

30
Q

Discuss the use and spectrum of fusidic acid

A
  • steroid antibiotics
  • can be used for staph infections eg oseomyelitis ,pneumonia and septicaemia
  • Combination with another anti-staphylococcal agent to prevent emergence of resistance
31
Q

Development of resistance of fusidic acid

A
  • inhibiting translocation

* used for skin infection for 5 days and conjunctivitis

32
Q

Discuss the pharmacokinetics of fusidic acid

A
  • Readily absorbed orally
  • widely distributed except for CSF
  • Penetrates into bone very well
  • 95% plasma protein bound
  • half life is 5-6 hrs
  • can be excreted in faces
  • can be administered topically
33
Q

What are the side effects of fusidic acids

A
  • hepatoxicity
  • avoid in pregnancy
  • IM- local tissue necrosis
  • local hypersensitivity
  • risk of kernicterus in neonates

contraindications
*hepatic disfunction

34
Q

Mupirocin

Spectrum

A

Spectrum: Gram pos. bacteria, effective against

methicillin-resistant Staphylococcus aureus

35
Q

Mupirocin Mechanism of action:

A

Inhibits protein and RNA synthesis also DNA
and cell wall synthesis
– Bactericidal

36
Q

Mupirocin

Pharmacokinetics:

A

Rapidly inactivated after absorption
– No systemic absorption
– Topical application only (topical & intranasal)
– Preparations contains polyethylene glycol,
may lead to toxicity

37
Q

Side-effects: Mupirocin

A

Mild stinging, burning, itching at site of
application
Caution: porphyria

38
Q

Ketolides

A

Semi-synthetic derivatives of erythromycin A →
broader spectrum
• Telithromycin
• Spectrum/Uses
– Similar spectrum to macrolides, H. influenzae
– Erythromycin–resistant strains of
pneumococcus

39
Q

Ketolides• Mechanism of action

A

• Mechanism of action
– Can bind to 2 sites on the bacterial ribosome,
with higher affinity than macrolides

40
Q

Ketolides

• Pharmacokinetics

A

Once daily dosing → 5 days
– Metabolised in liver, Excretion: biliary and
urinary

41
Q

Ketolides Side effects

A
  1. Inhibits liver enzymes
    2.Risk of potentially serious hepatotoxicity
    3.Respiratory failure → myasthenia gravis
    patients
    4.Visual disturbances
    5.Loss of consciousness
42
Q

Oxazolidinones uses

A 
Gram positive bacteria
– Cloxacillin-resistant staphylococci &
vancomycin-resistant enterococci, MRSA
– Mostly bacteriostatic
– Bactericidal against streptococci
– Drug resistant M. tuberculosis
43
Q

Oxazolidinones

• Mechanism of action

A

Prevents the formation of the ribosome complex
– Binds to 23S ribosomal RNA of the 50S
ribosomal subunit inhibits protein synthesis

44
Q

• Pharmacokinetics of Oxazolidinones

A

IV or oral (100% bioavailability)
– Metabolised, yield 2 inactive metabolites
– Non-renal clearance is approx. 65% of total

45
Q

Oxazolidinones

• Side-effects

A

Oxazolidinones

• Side-effects

46
Q

Lipopeptides

A

• Daptomycin in clinical use (IV)
• Naturally occurring compound found in soil Streptomyces
roseosporus
• Spectrum/Uses:
– Infections caused by multi-resistant bacteria
– Active against Gram pos. bacteria only
– S. aureus bacteraemia incl. right-sided infective
endocarditis
– Disrupting bacterial cell membrane function
– Inhibition of protein, DNA and RNA synthesis
– Large number of side effects (myopathy)

anti bacterial drugs (7 decks)

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