Quinolones, Folic Acid Antagonists and Urinary Antiseptics

Question 1

Fluoroquinolone targets _________ in Gram negatives and _________ in Gram positive bacteria

Answer 1

DNA gyrase, topoisomerase IV (bottom line they interfere with DNA production)

Question 2

Name 3 fluoroquinolones

Answer 2

ciprofloxacin, levofloxacin, moxifloxacin

Question 3

What infection is the use of fluoroquinolone tied to?

Answer 3

Clostridium infection and the spread of antimicrobial resistance in many organisms

Question 4

Fluroquinolones should be administered at least _________ hours before consumption of dairy products or substances that contain divalent cations

Answer 4

2 hours

Best on empty stomach

Question 5

What is the route of clearance of fluoroquinolones?

Answer 5

Most by renal except moxifloxacin (hepatic)

Question 6

What is the clinical indication of ciprofloxacin?

Answer 6

Highly active against Pseudomonas
Not recommended as a first line agent for simple UTI
Should be avoided in MRSA infections due to high rates of resistance
Traceller’s diarrhoea caused by e.coli

Question 7

Name the two respiratory quinolones

Answer 7

Levofloxacin and moxifloxacin; they have much better coverage against Gram positive organism especially S. pneumoniae and against atypical pathogens such as mycoplasma pneumoniae

Question 8

Name at least 3 adverse effects associated with the use of fluroquinolones.

Answer 8

1. Phototoxicity
2. Tendinitis or tendon rupture
3. Prolong QT interval
4. Peripheral Neuropathy
5. CDAD
6. Arthropathy ( not recommended for infant and children <18yo)
7. Aortic dissection
8. GI effects: nausea, vomiting and diarrhoea

Question 9

Which antibiotics are known to cause phototoxicity?

Answer 9

Tetracyclines, fluoroquinolones

Question 10

Fluoroquinolones are contraindicated in _________

Answer 10

1. Children < 18 years old
2. Pregnant and breastfeeding women
3. Avoid in G6PD deficiency
4. myasthenia gravis

Question 11

Name 3 folate synthesis inhibitors

Answer 11

Sulfonamides, trimethoprim, cotrimoxazole

Question 12

Folic acid is vitamin B9 that is needed in humans to produce healthy ___________

Answer 12

red blood cells

Question 13

Which enzyme does sulfonamide inhibit?

Answer 13

Dihydropteroate synthase

Question 14

Which enzyme does trimethoprim inhibit?

Answer 14

Dihydrofolate reductase

Question 15

Sulfonamides are only effective in bacteria that synthesize their own __________?

Answer 15

folic acid

Question 16

What are the adverse effects of Sulfonamides

Answer 16

1. crystalluria (resulting in nephrotoxicity)
2. hypersensitivity
3. kernicterus if taken by mum in late pregnancy. (sulfa drugs displace bilirubin from binding sites on serum albumin; bilirubin pass into cns as BBB is not fully formed)
4. hematopoietic
   disturbances

Question 17

G6PD deficient patients using sulfonamides can suffer from __________

Answer 17

hemolytic anemia

Question 18

Trimethoprim can cause __________ deficiency in humans

Answer 18

folic acid; resulting in megaloblastic anemia

Question 19

Q
Folic acid deficiency caused by trimethoprim can be managed by giving the patients _____________ .

Answer 19

Folinic acid

Question 20

Cotrimoxazole is a combination of which 2 antibiotics, and in what ratio?

Answer 20

Trimethoprim and sulfamethoxazole, 1:5 respectively

Question 21

Name at LEAST two indications for cotrimoxazole

Answer 21

1. UTI
2. Pneumocystis pneumonia caused by Pneumocystis jirovecii

Question 22

Name at LEAST 3 adverse effects related to the use of cotrimoxazole

Answer 22

1. GI related adverse effects like nausea, vomitting, CDAD
2. Rash
3. Blood disorders including megaloblastic anemia, leukopenia, and thrombocytopenia
4. Haemolytic anaemia in G6PD deficient patients

Question 23

Cotrimoxazole is contraindicated in which trimester(s) of pregnancy?

Answer 23

First and last trimester

Question 24

What is nitrofurantoin’s mechanism of action?

Answer 24

It is converted by the bacteria to a highly active intermediate, which disrupts the synthesis of DNA, RNA and metabolic processes.

Question 25

Nitrofurantoin is effective in treatment of _________ .

Answer 25

lower UTI

Question 26

Nitrofurantoin is effective against?

Answer 26

E coli and enterococci

Question 27

Nitrofurantoin can cause urine colour to turn _________ .

Answer 27

brown

Question 28

How is nitrofurantoin cleared?

Answer 28

Renal clearance

Question 29

G6PD deficient patients using nitrofurantoin are susceptible to ___________ .

Answer 29

Hematologic disturbances such as hemolytic anemia, leukopenia

Question 30

Name 3 groups of patients in whom nitrofurantoin may be contraindicated.

Answer 30

1. Patients with impaired renal function
2. Pregnant women (at term > 37 weeks) (fetus may have G6PD deficiency)
3. Infants <1 mth of age
4. G6PD deficiency pts

Question 31

What would be examples of recommended treatment options for simple UTI in healthy women of reproductive age?

Answer 31

Cotrimoxazole
Nitrofurantoin