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

Question 2

Name 3 fluoroquinolones

Answer 2

ciprofloxacin, levofloxacin, moxifloxacin

Question 3

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

Answer 3

2 hours

Best on empty stomach
- just like tetracycline

Question 4

Indications for fluroquinolones

Answer 4

Ciprofloxacin (2nd gen)

• gram -ve & enteric coliforms (GNR)
• traveller’s diarrhoea (e coli)/food pois (salmo)
• X UTI, MRSA (resistance)
• prostatitis (high [ ] in prostatic tissue)

Levo & moxifloxacin– Gram +ve & atypicals

Question 5

Name the two respiratory quinolones

Answer 5

Levofloxacin and moxifloxacin

Question 6

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

Answer 6

1. Phototoxicity
2. Tendinitis or tendon rupture
3. Prolong QT interval
4. Peripheral Neuropathy
5. GI distress– CDAD
6. Arthropathy

Question 7

Which antibiotics are known to cause phototoxicity?

Answer 7

Tetracyclines, fluoroquinolones

Question 8

Fluoroquinolones are contraindicated in _________

Answer 8

1. Children < 18 years old
2. Pregnant/Lactating women
3. Myasthenia gravis pt

Question 9

Name 3 folate synthesis inhibitors

Answer 9

Sulfonamides (sulfamethoxazole), trimethoprim, cotrimoxazole

Question 10

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

Answer 10

red blood cells

Question 11

Which enzyme does sulfonamide inhibit?

Answer 11

Dihydropteroate synthase (thus humans aren’t affected)

Question 12

Which enzyme does trimethoprim inhibit?

Answer 12

Dihydrofolate reductase

decrease tetrahydrof acid–> aa, purine, thymidine

Question 13

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

Answer 13

Trimethoprim and sulfamethoxazole, 1:5 respectively

Question 14

Combination of sulfonamide & trimethoprim has _______ effect

Answer 14

synergistic

bactericidal as block tetrahydrofolate pathway

Question 15

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

Answer 15

folic acid

Question 16

Sulfonamides can cause nephrotoxicity as a result of __________?

Answer 16

crystalluria

sulfonamide acetylated & conj in liver - retains toxicity to ppt at neutral/acidic pH

Question 17

Trimethoprim can cause __________ deficiency in humans

Answer 17

folic acid deficiency–> megaloblastic anemia, leukopenia, thrombocytopenia

AVOID in 1st & 3rd trimester pregnancy

Question 18

Usage of sulfonamides in last trimester can cause __________ in newborns

Answer 18

kernicterus

Question 19

G6PD deficient patients using sulfonamides can suffer from __________

Answer 19

hemolytic anemia

Question 20

Adverse effects of sulfonamides

Answer 20

1. Hemolytic anaemia in G6PD deficient pt
2. Crystalluria (cloudy urine)– nephrotoxicty: can alkalinise urine or hydration
3. Kernicterus newborns: drug taken late in preg
4. Hypersensitivity

Question 21

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

Answer 21

Folinic acid 
(does not take part in pathway but is interchangeable conversion to tetrahydrf)

Question 22

Name at LEAST two indications for cotrimoxazole

Answer 22

1. Uncomplicated UTI
2. Pneumocystis pneumonia (Pneumocystis jiroveci)
3. MRSA
   ? meningitis as good CSF penetration/ cross BBB

Question 23

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

Answer 23

other than that of sulf & trimethoprim

1. Glossitis
2. Rash

Question 24

What’s a urinary antiseptic agent?

Answer 24

Nitrofurantoin

Question 25

What is nitrofurantoin’s mechanism of action?

Answer 25

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

Question 26

Nitrofurantoin is effective in treatment of _________ .

Answer 26

lower UTI
- E coli
- Enterococci
X Pseudomonas, proteus, klebsiella, enterobacter

Question 27

How is nitrofurantoin cleared?

Answer 27

Renal clearance

rapidly absorbed & rapidly cleared to urine

Question 28

Nitrofurantoin can cause urine colour to turn _________ .

Answer 28

brown

** tell pt otherwise think it’s blood

Question 29

Adverse effects of nitrofurantoin

Answer 29

1. in elderly *pulm toxicity, peripheral neuropathies (rare) –> consider instead cotrimoxazole
2. GI symptoms– use microcrystalline
3. X GP6D Def
4. Chol jaundice/hepatocellular damage w nitro-redu metab producing free radicals (rare)

Question 30

G6PD deficient patients using nitrofurantoin are susceptible to ___________ .

Answer 30

Hematologic disturbances such as hemolytic anemia, leukopenia

Question 31

What is G6PD, and why is it important in red blood cells?

Answer 31

The glucose-6-phosphate dehydrogenase (G6PD) enzyme is the central factor of the antioxidant defense system in red blood cells, which helps maintain high levels of reduced glutathione (GSH) and nicotine adenine dinucleotide phosphate (NADPH), to protect the RBC from oxidative damage caused by reactive oxygen species.

Question 32

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

Answer 32

1. Patients with impaired renal function
2. Pregnant women (at term > 37 weeks)
3. Infants <1 mth of age

Question 33

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

Answer 33

1. Cotrimoxazole

2. Nitrofurantoin

Question 34

Upper UTI

Answer 34

1. IV ceftriaxone

Question 35

Tx atypicals

Answer 35

1. tetracycline
2. macrolides (pregnant pt)
3. fluoroquinolones