A.bac: DNA Syn inhibitors and Folate inhibitors

Question 1

DNA Synthesis inhibitors

Folate Inhibitors

Answer 1

Dna: Fq,Quinolones, Metronidazole
Folate: Sulfonamides, Trimethoprim

Question 2

MOA of FQ/Q

Answer 2

DNA gyrase inhibitor (topoisomerase II) and topoisomerase IV: makes cell inaccessible and leads to cell death.
Nalidixic acid (urinary disinfectant)
Different quinolones inhibits different extent of topoisomerase II and IV

Question 3

Fq are indicated for?

Cipro, Levo, Moxi dosage forms.

Answer 3

PO and IV

Question 4

FQ drug generations

Answer 4

1st: Nalidixic acid, Norflox- least acty to +-ve
2nd: Oflax, Cipro- most eff. for -ve
3rd: Levoflox (respiratory), both Gati Moxi improved for +ve
4th: Travoflox, basiflox

Question 5

Grams for Gyrase and Topo.

Nalidixic

Answer 5

DNA gyrase seems more important in gram –ve. Topoisomerase IV in gram +ve. Nalidixic acid is primarily against gram -ve

Question 6

Q chelation

Answer 6

Quinolones chelate with polyvalent ions such as Fe, Al, Mg, Ca to form less water-soluble and complexes and thus decrease considerable potency.

Question 7

FQ and Qs are CI in children, less than 18 year, pregnant women due to its?

Answer 7

Cartilage erosion

Question 8

Fluroquinolone increase INR in patient receiving warfarin, therefore monitor?
Fluroquinolones can cause hypo or hyperglycemia, therefore monitor?

Answer 8

prothrombin time (PT)
blood sugar levels in diabetic patient

Question 9

Fluroquinolones at higher alkaline pH can cause?
Cipro is the drug of choice.
The only Quinolone that is taken empty stomach?

Answer 9

crystalluria
travelers diarrhea
norfloxacin (*no food)

Question 10

Metronidazole drug, classification, MOA

Answer 10

Nitroimidazole class - as an anti protozoal antibiotic

Inhibit nucleic acid synthesis by disrupting DNA of microbial cells.

Question 11

Metronidazole is effective against

Answer 11

C. difficle, B. fragilis, amebia, C. vaginalis (bacterial vaginitis), Giardiasis, trichomonas, H. pylori, and P.colitis

Question 12

Metro inhibits CYP2C9 which will interact to drugs metabolized by this enzyme.

Answer 12

Warfarin, Lomitapide

*metro will discolor urine and CI in preg

Question 13

Sulfa drugs MOA

Answer 13

inhibit synthesis of dihydropteroic acid

Question 14

Folate antagonist sulfa drugs (Cotrimoxazole) MOA on DNA synthesis

Answer 14

Dihydroteroate diphosphate + PABA
DHP synthase ⬇️ ✖️sulfonamides
dihydroteroic acid ➡️ dihydrofolic acid
DHF reductase⬇️ ✖️Trimethoprim
tetrahydrofolic acid ➡️ thymidine ➡️ DNA

Question 15

A 22-year-old patient currently using cotrimoxazole for UTI, reported sever blisters on mucus membrane, and eyes. What are the possible reactions?

Answer 15

Stevens Johnson Syndrome, it is a hypersensitive reaction of sulfadrugs.

Question 16

What are the folic acid synthesis inhibitors?

Answer 16

Sulfadrugs, methotrexate, trimethoprin, 5FU, pyremethamine, and dapsone.

Question 17

Patient with G6PD deficiency, takes sulfadrugs can cause?

Answer 17

Hemolytic anemia

Question 18

Hypersensitive reactions of sulfadrugs most commonly involve?

Answer 18

Skin and mucous membrane: manifestation include skin rash, exofoliative dermatitis, and photosensitive. Drug fever and serum sickness also may occur.

Question 19

Life threatening hepatitis caused by sulfadrug toxicity or sensitization rare SE, the signs and symptoms include?
Sulfamethoxazole have high frequency of skin hypersensitive reaction in patient with?
• If used in last trimester of pregnancy, can cause?

Answer 19

SEs: HE, n&v and jaundice

• AIDS
• kernecterus in new born.

Question 20

Cotrimoxazole is DOC for?

Oral susp. of this storage

Answer 20

P. carinii pneumonia PCP

room temperature

Question 21

This antibiotic inhibits both DNA RNA synthesis.

CI and DOC

Answer 21

Nitrofurantoin.
Not used in renal diseases or contraindicated in CrCl <60 ml/min
DOC for UTI and also used as prophylaxis for UTI in pregnancy 100mg BID for 7 days.

Question 22

Sulfonamides that are orally absorbable and non.

Answer 22

abs: Sulfadoxine, Sulfadiazine, Sulfamethoxazole -UTI
non: Sulfasalazine -ulcerative colitis, enteritis and other bowel inflamm. Aft PO, act locally on lumen of GI tract

Question 23

Topical Sulfonamides

Answer 23

Sodium sulfacetamide -ophthalmic soln. for bac conjunctivitis
Mafenide acetate and Silver sulfadiazine- skin infx and burn oint