Brainscape's Knowledge GenomeTM

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


See full index

Human Diseases Yr3 > Antibiotics and Antivirals > Flashcards

Antibiotics and Antivirals Flashcards

1
Q

What is meant by

a) Bacteriostatic
b) Bacteriocidal

A

a) Inhibits bacterial growth/replication

b) Kills the bacteria

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

In the gram-stain what colour are organisms that are

a) gram +ve
b) gram -ve
c) Have thick peptidoglycan wall

A

a) Purple
b) Pink
c) Purple (gram +ve)

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

What is the mechanism of action of the Beta-lactams e.g. penicillin, cephalosporins, carbapenems

A

Inhibition of peptidoglycan synthesis by irreversibly binding to the enzyme (penicillin binding proteins) that catalyses the crosslinking of peptidoglycan subunits

Ie prevents cell wall synthesis

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

What is the mechanism of action of vancomycin?

A

Disruption of peptidoglycan cross-linkage by binding to peptidoglycan monomers (n-acetylmuramic acid)

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

What is the mechanism of action of bacitracin?

A

Disrupts lipid carrier require for glycan transport across the bacterial cell membrane

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

Which drugs work by altering the cell/plasma membrane, causing depolarisation of the cell and leakage of its contents?

A
  • Polymyxins (B+E)

- Daptomycin

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

Which drugs act on the 30s ribosome site to prevent protein synthesis and what actions do they inhibit?

A

Tetracyclines - entry of incoming acetyl tRNA

Aminoglycosides e.g. gentamycin - correct reading of mRNA

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

Which drugs act on the 50s ribosome site to prevent protein synthesis and what actions do they inhibit?

A

Macrolides e.g. erythromycin - Translocation
Chloramphenicol - Transpeptidation
Clindamycin - Translocation

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

What do Quinalones (e.g. Ciprofloxacin) effect?

A

DNA

They inhibit DNA gyrases or topoisomerases required for supercoiling of DNA

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

What does Metronidazole effect?

A

DNA
Cause inhibition of DNA replication, loss of DNA helical structure and fragmentation of existing DNA and mutates bacterial genome

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

What does Rifampicin effect?

A

RNA (transcription)

Binds to RNA polymerase

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

What pathway is a target for the drugs sulphonamides, trimethoprim and dapsone?

A

Folate synthesis leading to the synthesis of DNA

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

What is the MOA of sulphonamides in the folic acid pathway?

A

Prevent PABA being converted to dihydrofolic acid by dihydropterote synthetase - enzyme not active in humans

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

What is the MOA of trimethoprim?

A

Inhibits dihydrofolate

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

What is MRSA treated with?

A
  • Vancomycin
  • Teicoplanin
  • Linezolid (inhibit protein synthesis)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the mechanisms bacteria have adopted to prevent the action of antibiotics (ie resistance)?

A
  • Efflux of antibiotic - reverse transport systems in the membrane e.g. tetracycline transported out
  • Enzyme modification
  • Enzyme degredation - e.g. penicillinases cleave beta-lactam ring on penicillin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the acquired resistance mechanism ‘Vertical gene transfer’?

A

Spontanous mutation causing resistance genes which are transferred directly to all bacteria progeny during DNA replication

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

What are the 3 forms of horizontal gene transfer?

A

1) Conjugation - direct cell to cell contact transferring plasmids
2) Transformation - DNA taken up from external environment
3) Transduction - Bacteriophages transfer DNA

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

What antibiotics are contraindicated in pts with liver disease?

A
  • Tetracyclines (can cause jaundice, fever and fatty liver)
  • Macrolides e.g. erythromycin (bile retention and jaundice)
  • Metronidazole (metabolised in liver by p450 so half life and clearance prolonged and adverse reaction)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the safest antibiotic to use in pts with liver disease?

A

Penicillin

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

What antibiotics are contraindicated in pts with kidney disease?

A
  • Tetracycline

- Reduce dose of amoxicillin and erythromycin

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

What antibiotics are contraindicated in pts with glandular fever/infectious mononucleosis?

A

Ampicillin and amoxicillin as they cause rashes

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

What antibiotics are contraindicated in pts with lymphocytic leukaemia?

A

Ampicillin and amoxicillin as they cause rashes

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

What antibiotics are contraindicated in pts with pre-existing diarrhoea?

A

Clindamycin and co-amoxiclav

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Which antibiotic is the safest option for pregnancy and breastfeeding?

A

Amoxicillin

erythromycin also safe

26
Q

What is the advice on metronidazole and pregnancy / breast feeding?

A
  • High doses are contraindicated

- Avoid in women at risk of pre-term labour

27
Q

What is the advice on clindamycin and pregnancy / breastfeeding?

A

Caution in breast feeding as risk of diarrhoea, candidiasis and colitis in newborns

28
Q

What is the advice on co-amoxiclav and pregnancy / breastfeeding?

A

Avoid in women at risk of preterm labour as risk of necrotising enterocolitis

29
Q

What is the advice on tetracycline and pregnancy / breastfeeding?

A
  • Avoid in pregnancy

- Risk of neural tube defects, clefts, cardiovascular defects, discolouration of dental tissues

30
Q

What antibiotics should be avoided if a patient has anaphylactoid reactions to penicillin?

A

Cephalosporins (have beta-lactam ring)

31
Q

What is the major adverse effect pseudomembranous colitis? What antibiotic especially causes this?

A
  • Inflammation of the colon associated with C.diff. Severe = toxic megacolon
  • Clindamycin
32
Q

What drug is the most common cause of the major adverse effect idiosyncratic liver damage?

A

Co-amox, and has been reported for amoxicillin

33
Q

What drug can cause the major adverse effect hypokalaemia and what do its symptoms include?

A
  • Penicillin

- Weakness, constipation, cardiac arrhythmias, leg cramps etc

34
Q

What drug is used to improve compliance in alcohol dependent patients?

A

Disulfiram

35
Q

What antibiotic is it advised against consuming alcohol whilst taking and after 48 hours of stopping treatment due to nausea, vomiting and tachycardia effects?

A

Metronidazole

36
Q

Which antibiotics have drug interactions with anti-metabolite drugs?

A

Penicillin and tetracyclines

37
Q

Which antibiotic reacts with allopurinol used for gout causing skin rashes?

A

Amoxicillin

38
Q

Which antibiotics will increase the effect of warfarin and cause greater risk of bleeding?

A

Erythromycin, penicillin, metronidazole

39
Q

In what situation is Amoxicillin the first choice for treatment?

A
  • For dento-alveolar infections and to limit the spread of infection
  • Prior to implants or extraction of those at risk of osteoradionecrosis
40
Q

In what situation is Metronidazole the first choice for treatment?

A
  • Necrotising periodontal disease and pericoronitis
  • In penicillin allergies
  • Adjunct to amoxicillin for dento-alveolar infection (extends spectrum of activity to anaerobes)
41
Q

Why is clindamycin more appropriate than erythromycin as a second line drug?

A

Some bacteria have developed resistance to erythromycin and has increased adverse effects

42
Q 
A patient you are treating has the following symptoms: 
- Elevated temperature 
- Evidence of systemic spread 
- Local lymph gland involvement
They have an acute dento-alveolar infection / peridontal abscess. 
What antibiotics do you prescribed 
a) First line? 
b) Second line?
A

a) Amoxicillin 500mg TDS 5 days
If penicillin allergy: Metronidazole 400mg TDS 3 days or Clindamycin 150-300mg QDS 5 days

b) Co-amoxiclav 500/125mg TDS 5 days or Clindamycin 150-300mg QDS 5 days

43
Q

A patient you are treating has pericoronitis which you have irrigated but they have an elevated temperature and evidence of systemic spread. What do you prescribe:

a) First line?
b) Second line?

A

a) Metronidazole 400mg TDS 3 days

b) Amoxicillin 500mg TDS 3 days or clindamycin 150-300mg QDS 7 days

44
Q

A patient you are treating has necrotising ulcerative gingivitis which you have provided scaling and OHI. What would you prescribe:

a) First line?
b) Second line?

A

a) Metronidazole 400mg TDS 3 days

b) Amoxicillin 500mg TDS 3 days or Clindamycin QDS 7 days

45
Q

A patient you are treating has sinusitis which is prolonged and severe. What would you prescribe:

a) First line?
b) Second line?
c) Third line?

A

a) Amoxicillin 500mg TDS 5 days and Ephedrine Hydrochloride 0.5% nasal drops QDS 7 days. Review healing after 2 weeks
b) Doxycycline first day 200mg OD then 100mg OD 6 days
c) Co-amoxiclav 500/125mg TDS 5 days

46
Q

A patient you are treating has oral antral communication/ fistula. What would you prescribe:

a) First line?
b) Second line?
c) Third line?

A

a) Amoxicillin 500mg TDS 5 days and Ephedrine Hydrochloride 0.5% nasal drops QDS 7 days. Review healing after 2 weeks
b) Doxycycline first day 200mg OD then 100mg OD 6 days
c) Co-amoxiclav 500/125mg TDS 5 days

47
Q

A patient you are treating needs antibiotic cover due to head and neck radiotherapy/ immunosupression. What would you prescribe:

a) First line pre op and post op?
b) Second line pre op and post op?

A

a) Pre op = Amoxicillin 3g 1 hr before and chlorhexidine 0.2% 10ml rinse pre XLA
Post op = Amoxicillin 500mg TDS 7 days and chlorhexidine 0.2% rinse twice daily for 2 weeks

b) Pre op = Clindamycin 600mg 1 hr before and chlorhexidine 0.2% pre XLA
Post op = Clindamycin 150mg QDS 7 days and chlorhexidine rinse twice daily for 2 weeks

48
Q

What dental conditions are antibiotics not appropriate for?

A
  • Early pericoronitis
  • Post op oedema
  • Fibrinolytic conditions e.g. alveolar osteitis
  • Non-bacterial infections e.g. fungal and viral
49
Q

Why are antibiotics given 1 hr before surgery?

A

Blood clots impenetrable by antibiotics 3hrs after formation

50
Q

What type of antiviral agents are anti-herpetic agents predominantly?

A

Nucleoside analogues

51
Q

What is Aciclovir? How does it work?

A
  • Analogue of guanosine
  • Transformed into active state by viral enzymes
  • Incorporates into viral DNA to inhibit DNA synthesis
52
Q

For Aciclovir:

a) What is its half life?
b) Why can it be used for viral encephalitis?
c) Where is it excreted?
d) How is it administered?

A

a) 2.5 hrs
b) Crosses the blood brain barrier
c) Kidneys
d) Topical or IV

53
Q

What is Idoxuridine?
How does it work?
How is it administered?

A
  • Antiviral that is a thymidine analogue
  • Phosphorylated in cells and incorporated intp cellular and viral DNA
  • Mainly used against DNA viruses
  • Too toxic for systemic use so only used topically
54
Q

What is Zidovudine (AZT) and what is it used against?

A
  • Thymidine analogue

- HIV-1

55
Q

For Zidovudine (antiviral):

a) What is the MOA?
b) What drugs have a synergistic effect?
c) How is it administered?

A

a) Inhibits viral RNA-dependent DNA polymerase so stops growing strand of DNA
b) Aciclovir and interferon
c) Orally or IV

56
Q

What are the unwanted effects of the antiviral Zidovudine?

A
  • Anaemia
  • Granulocytopenia (fewer cells)
  • Must do regular blood count every 2 weeks
57
Q

What are non-nucleoside analogues used to treat? Name the drugs.

A
  • AIDS

- Nevirapine and Delavirdine

58
Q

What are the antiviral interferons and what do they do?

A
  • Group of cytokines (alpha, beta, gamma) and are glycoproteins produced by the body in response to a virus
  • Enhance the cytotoxic capacity of T-lymphocytes
59
Q

What are the 3 antibiotics that inhibit cell wall synthesis?

A

Beta lactams (penicillin, cephalosporin, carbapenems)
Vancomycin
Bacitracin

60
Q

Name 2 diseases caused by prions

A

Bovine spongiform encephalitis (cattle) /BSE
Creutzfeldt-Jakob disease (CJD)

Human Diseases Yr3 (6 decks)

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