Nucleic Acid Synthesis Inhibitors Flashcards
didnt add fluoroquinolones yet
What are the classes of nucleic acid synth inhibitors?
Fluoroquinolones
- 1st: nalidixic acid
- 2nd: ciprofloxacin
- 3rd: levofloxacin
- 4th: gemifloxacin, moxifloxacin
Sulfonamides
- sulfmethoxazole
- sulfadiazine
- sulfasalazine
Trimethoprim
Co-trim-oxazole
-combination of trimethoprim and sulfmethoxazole
Sulfonamides? What are they? MOA?
PABA analogs
in bacteria PABA –> folic acid –> DHF –> THF
enzymes:
dihyrdrofolate synth –> dihydrofolate reductase –> dihydrofolate reductase
Sulfonamides replace PABA –> decrease purine synthesis
*competitive inhibitors
Sulfonamides are bacteriostatic or cidal? Spectrum?
gram positive and gram negative
all nucleic acid synthesis kill gram pos and neg
bacteriocidal
sulfonamides Resistance mech? 4
plasmid transfer or random mutation
- in dihydropteroate synthase
- inc PABA
- dec cell perm
- dec drug accumulation
Sulfonamides admin? Used to treat
topical, oral
Topical: ocular or burn infections
Oral: UTIs
Sulfasalazine: oral: ULCERATIVE COLITIS, ENTERITIS IBD
Sulfonamides adverse effects?
- Hypersensitivity
- hematopoietic disturbances (in pts with G6PDH def)
-crystalluria
sulfonamides are acetylated in the liver –> precipitate at neutral or acidic pH –> kidney damage
-kernicterus
sulfa drugs displace other drugs from albumin
Sulfonamides contraindications?
Newborns and babies under 2 months
kernicterus
Trimethoprim bacteriocidal or static? spectrum?
affects both gram positive and negative
- bacterioSTATIC
- doesnt kill just stops growth
Trimethoprim MOA?
inhibits dihydrofolate reductase
inhibits (not 100% stops)
purine
pyrimidine
AA (methionine) synthesis
Trimethoprim contraindications
DO NOT GIVE IN PREGNANCY
-antifolate effects in mammals
Trimethorprim used to treat?
UTIs, bacterial prostatitis and vaginitis
high concentrations get to prostatic and vaginal fluids
What cephalosporin is known to cause kernicterus?
Ceftriaxone
Cotrimoxazole is a combination of what? MOA?
trimethoprim (dihhyrdofolate reducatse inhib) and sulfamethoxazole (sulfonamide - PABA analog)
Bacteriocidal
-synergism: ibhibits sequential steps in THF synth
Cotrimoxazole used to treat?
Uncomplicated UTIs
(DOC)
Opportunistic infections in the immunocompromised (ie. cancer –> chemo)
Cotrimoxazole admin?
oral or IV
Cotrimoxazole AE?
dermatologic
hematologic (like sulfa drugs )
higher AE in AIDS patients
Contrimoxazole contraindications?
Contraindicated in pregnancy
esp 1st trimester ***
remember cotrimoxazole contains trimethoprim (red folate therefore also contraindicated in pregnancy)
Name of miscellaneous drug? What does it treat?
Polymyxcin B: cationic detergent
MOA: binds to bacterial cell membranes
binds to endotoxins (LPS) –> inactivates it
bacteriocidal
treats infected superficial skin lesions
Polymyxin B admin?
topical only
infected superficial skin lesions
systemically –> severe nephrotoxicity
Polymyxcin B spectrum?
gram positive only
remember MOA : bind to endotoxins
What is the name of the urinary antiseptic? spectrum?treats? admin?
Nitrofurantoin
gram positive and negative
(cover all the bases)
tx: lower UTIs
admin: oral
Nitrofurantoin AE?
hemolytic anemia in people that are G6PDH deficient
recall MOA:
in urine, nitrofurantoin gets reduced –> forms reactive intermediate which damages bacterial DNA
Nitrofurantoin bacteriocidal or static?
can be both
Nitrofurantoin contraindications>
Mom at full term
infants under a month
babies have immature G6P DH
-and people with renal insufficiency
remember the drug basically stays in the urine and has no systemic effects
