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Flashcards in Antifolates Deck (9)
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1
Q

Sulfonamide activity

A

STATIC

2
Q

Sulfonamide MoA

A

they are structural analogs of p-aminobenzoic acid, so they inhibit the synthesis of tetrahydrofolic acid specifically by inhibiting dihydropteroate and preventing PABA conversion to dihydrofolic acid in DNA synthesis

3
Q

Sulfonamide toxicity

A

hypersensitivity reaction, hemolytic anemia, aplastic anemia, agranulocytosis (immunosuppresion), crystalluria, neurotoxicity

4
Q

Why do sulfonamides cause neurotoxicity?

A

they inhibit the enzyme sepiapterin reductase, which is involved in biosynthesis of neurotransmitters

5
Q

How are sulfonamides distributed in the body?

A

well-distributed including CSF and placenta, readily absorbed from GIT

6
Q

What are the mechanisms of resistance against sulfonamides?

A

expression of altered enzyme dihydropteroate synthase, increase in PABA production, development of alternate pathway for DNA synthesis, decrease in bacterial permeability

7
Q

What is Bactrim?

A

sulfamethoxazole and trimethoprim

8
Q

What is the MoA of Bactrim?

A

inhibition of DHFR (trimethoprim) therefore inhibiting the conversion of dihydrofolic acid to tetrahydrofolic acid

9
Q

Bactrim toxicity

A

leukopenia, megaloblastosis, thrombocytopenia