Antibiotics - Nitroimidazole

Question 1

What is the core drug in the Nitroimidazole class?

1 - Amoxicillin
2 - Metronidazole
3 - Co-Amoxiclav
4 - Vancomycin

Answer 1

2 - Metronidazole

Question 2

Metronidazole is the core drug in the Nitroimidazole class. What is its mechanism of action?

1 - binds to penicillin binding protein
2 - release nitrosa free radicals, damaging DNA
3 - bind to 50S ribosome
4 - irreversibly binds the 30S ribosome subunit and inhibits protein synthesis

Answer 2

2 - release nitrosa free radicals, damaging DNA
- without function DNA the cell cannot replicate and will die

Question 3

Metronidazole is the core Nitroimidazole that we need to be aware of. Is this a bactericidal or bacteriostatic?

Answer 3

• bactericidal

Question 4

Metronidazole is the core Nitroimidazole that we need to be aware of. Is this a broad or narrow spectrum antibiotic?

Answer 4

• broad spectrum
• anaerobic bacteria and protozoa (parasite)

Question 5

Metronidazole is the core Nitroimidazole and is used to treat oropharyngeal gram negative anaerobes. Which of the following is Metronidazole indicated for to treat?

1 - dental infection
2 - infected human/animal bites
3 - aspiration pneumonia
4 - all of the above

Answer 5

4 - all of the above

Question 6

Metronidazole is the core Nitroimidazole and can be used to eradicate Helicobacter pylori that can cause peptic ulcers. This is typically combined with which 2 of the following?

1 - amoxicillin or cephalosporins
2 - omeprazole
3 - antacids
4 - Hydrocortisone

Answer 6

1 - amoxicillin or cephalosporins
2 - omeprazole

Question 7

Metronidazole is the core Nitroimidazole and is indicated in the treatment of which 2 of the following if they contain Gram negative bacteria?

1 - intraabdominal infection
2 - UTI
3 - nephrolithiasis
4 - pelvic inflammatory disease

Answer 7

1 - intraabdominal infection
4 - pelvic inflammatory disease

Question 8

Metronidazole is the core Nitroimidazole that can be used to treat which condition if Vancomycin cannot be given orally as the 1st line treatment?

1 - UTI
2 - COPD exacerbation
3 - clostridium dicicil colitis
4 - joint infection

Answer 8

3 - clostridium dicicil colitis

Question 9

Which protozoal infections is Metronidazole indicated in as treatment?

1 - trichomonal vaginal infection
2 - ameboic dysentry
3 - giardiasis
4 - all of the above

Answer 9

4 - all of the above

Question 10

Metronidazole is the core Nitroimidazole. Which of the following is NOT an adverse event of this medication?

1 - GI upset
2 - immediate and delayed hypersensitivity
3 - peripheral and optic neuropathy
4 - seizures
5 - encephalopathy
6 - QT-prolongation

Answer 10

6 - QT-prolongation

• peripheral and optic neuropathy, seizures and encephalopathy generally occurs when using high doses for prolonged periods

Question 11

Metronidazole is the core Nitroimidazole. When should the dose of this drug be reduced when indicated for treatment?

1 - severe liver disease
2 - renal impairment
3 - cardiac disease
4 - diabetes

Answer 11

1 - severe liver disease
- metabolised by cytochrome P450, so if liver is damaged it cannot be metabolised and could become toxic

Question 12

Metronidazole is the core Nitroimidazole. This drug should not be taken with alcohol, why?

1 - alcohol inhibits cytochrome P450
2 - acts as cytochrome P450 agonist and limits its efficacy
3 - inhibits acetaldehyde dehydrogenase
4 - all of the above

Answer 12

3 - inhibits acetaldehyde dehydrogenase
- responsible for clearing alcohol from the body

• if metronidazole is taking with alcohol it can cause unpleasantness, including flushing, headaches, nausea and vomiting

Question 13

Metronidazole is the core Nitroimidazole. This drug is metabolised by cytochrome P450, but also has an inhibitory effect. What affect can this then have on Warfarin?

Answer 13

• warfarin is not metabolised
• levels of warfarin remain high and increase the risk of bleeding

Question 14

What is the preferred route of administration for Metronidazole?

1 - oral
2 - IV
3 - IM
4 - suppository

Answer 14

1 - oral
- standard dose = 400mg/8 hourly

• IV is reserved for severe infections of when oral is not possible
• standard IV dose = 500mg/8 hourly

Question 15

Metronidazole can be prescribed for topical administration for which of the following?

1 - bacterial vaginosis
2 - skin infections (rosacea)
3 - infected skin ulcer (reduce smell)
4 - all of the above

Answer 15

4 - all of the above

Question 16

When prescribing any antibiotics, in accordance with antibiotic stewardship, which of the following must be document on the prescription and in the patients notes?

1 - indication
2 - review date
3 - treatment duration
4 - all of the above

Answer 16

4 - all of the above

Question 17

If prescribed as IV, how long should it be before the antibiotics are switched to oral where appropriate?

1 - 12h
2 - 24h
3 - 48h
4 - 72h

Answer 17

3 - 48h

Question 18

Broad spectrum antibiotics are prescribed empirically, when we do not know the specific cause of the infection. However, what is the main driver to switch antibiotics to a narrow spectrum antibiotic?

1 - cost
2 - patients request
3 - microbiology results
4 - allergies

Answer 18

3 - microbiology results