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20 Cards in this Set

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Describe "Sulfonamides"
Derivatives of PABA (ingredient in sunscreen), Prontosil as precursor, 1st agents used against bacteria
Described by Hildegard Domagk
List some diseases in which sulfonamides play important role
Bronchitis, IBD, Otitis, PCP, Burns, UTI, Sinusitis
List some rapidly absorbed Sulfonamides
Short acting: 4-8 hrs
Intermediate Acting:12-18 hrs
Long acting
List some poorly absorbed Sulfonamides
Sulfasalazine used in IBD&RA
In GI it converted into 5-ASA and Sulfapyridine (revesible infertility due to change count&morphology)
Pentasa: deliver to enter GI and small intestine
Asacol: terminal ileum and beyond
Olsalazine: a prodrug, couple to 5-ASA split by intestinal bacteria
Rowasa: Rectal enema and suppositories, used for proctosigmoiditis
OPRA drugs: Olsalazine, Pentasa, Rowasa, Asacol are formulated to be released at a specific GI location. They are poorly absorbed and active in intestinal lumen
What are the uses of the following Sulfonamides: Sulfacetamide, Mafenide, Silver Sulfadiazine?
Sulfacetamides: Ophthalmic infection like trachoma (Chlamydia)
Mafenide: for burns
AE: Allergy,pain, Carbonic Anhydrase inhibition
Silver Sulfadiazine: prevents infection of burnt surface and chronic ulcers with minimal allergy
AE: for Mafenide
paracarboxybenzenesulfonamide is also CAI
Stop Mafenide and infuse Sodium Bicarbonate to prevent acidosis.
What's the mechanism of action of Sulfonamides?
Competitive inhibitors of Dihydropteroate Synthase, enz that add PABA to Dihydropteroic acid, as precursor of folic acid.
Sulfonamides are incorporated into a dysfunctional folate. they Bacteriostatic, means immune System is required to eliminate the infection.
Describe Sulfonamides Kinetics
Most of them are well absorbed from GI, moderate tissue penetration.
Biotrans/liver excr/Kidneys.
Inactivation by acetylation
They can cross placenta and produce antibact and toxic effect to the fetus.
Decrease solubility in acidic urine, precipitation of metabolites or the drug, but higher conc. in urine provide usefulness in UTI
In renal failure Biodegraded metabolites are toxic.
Slow vs fast acetylators
Therapeutic uses?
Sulfisoxazole+Phenazoppyridine (Dye): UTI, Cystitis
Sulfadiazine+Pyrimethamine=Folonic acid+Hydration =DOC for Toxoplasmosis
Short acting Sulfas: Norcardia, trachoma, LVG
Sulfamethaxasole+Trimethoprim for UTI, RTI, PCP,
Sulfadoxine+Pyrimethamine as prophylaxis in Malaria
Sulfamethoxazole+Phenazopyridine for UTI
How do bacteria resist Sulfonamides?
Lowered affinity/sensitivity to Dihydropteroate Synthase
Incr. in PABA from external sources like procaine administration and pus, tissue breakdown
Use preformed folic acid/alternative pathway for essential metabolites
decrease permeability, less intrtacellular accumulation./ incr. acetylation
1. Lowered sensitivity to the enz.
2. Increase usage of Paba from outside and alternative sources
3. Less permeability and fast acetylation
What are the AE of Sulfonamides?
Hypersensitivity; Stevens Johnson Syndrome
Cross Sensitivity: w/ other drugs: Thiazides, oral Hypoglycimic drugs
Crystalluria: low solubility of some types, Sulfadiazine used in AIDS for Toxo.
Acute Hemolytic Anemia: pts w/ G6PD Deficiency
kernicterus: in neonates&Prematures b/c they can displace bilirubin from binding site, premature BBB can allow passage of Sulf.
Displacement of drugs like METHOTRAXATE, TOLBUTAMIDE, WARFARIN, Hydantoin, from plasma binding site, incr. of plasma level
Drug interaction: Methenamines releases formaldehydes in acid media of urine, forming complex w/ sulf.
What's the struture of Trimethoprim? Use as?
similar to folic acid, weak base that can get caught in acidic media, reaching high conc. in the prostate &vaginal fluid. excr. in urine mostly unchanged
SMZ-TMP (Co-trimoxazole) has a synergistic effect on blockage of Dihydrofolic acid and tetrahydrofolic acid synthesis. Same t1/2,SMZ-TMP ratio 5:1
Sequential blockage of Dihydropteroate Synthase and Dihydrofolate reductase
Leading to impaired Purine,pyrimidine and AA synthesis causing impaired DNA synthesis
What's the spectrum of activity of SMZ-TMP co-trimoxazole?
No anearobic cpverage.
Effective against: E.coli, Salmonella and PCP, alternative to Doxycyclin and Streptomycin for NOCARDIA
ESPN: Ecoli, Salmonella, PCP, Nocardia
AE of SMZ-TMP/Co-trimoxazole?
Megaloblastic anemia in folate deficient pt., Leukopenia, Thrombocytopenia
Transient Jaundice
Skin rashes, exfoliative dermatitis in eldery
TMP: Treat Marrow Poorly
TMP/SMX clinical uses?
TMP: Respiratory tract: Strep. Pneumonia, H. infl, otitis Media, Sinusitis, Bronchitis, Pneumonia
GIT: Ecoli, Salmonella, Shigella
UTI, Prostatis, urethritis by ecoli
T(Tree) Resp. tract
M (Mouth) GIT
P (Pee) UTI
SMX (Syndrome) AIDS-PCP
List other Antibacterial agents used in UTI
Methenamine Mandelate
FQ: aredivided in 4 generations
based on spectrum of actity
what are the 1st generation Quinolones?
Nalidixic Acid (not used) & Norfloxacin
narrow spec, for UTI
2nd generation of Quinolones?
Ciprofloxacin, Ofloxacin
Greater activity against G(-)bacteria, Gonococcal, Mycobacteria (atypical included) mycoplasma pneumonia
Cipro & O (-FLOXACIN)
2,3,4 Gen have broa spec.
3rd Gen. of Q?
Lomefloxacin, Gatifloxacin, Sparfoxacin
Greater acivity against G(+)cocci, some MRSA strain and Enterococci, less activity against G(-)
Gati par(s) a Lome
4th Gen. of Q?
Moxifloxacin & Trovafloxacin
Broadest Spec. against ANAEROBES.
What's the mechanism of action of Quinolones?
Inh. of Gyrase mediated by supercoiling of the DNA. Post antibiotic effect.
Newwe Q are effective against G-,G+, and anearobic infection. that includes skin, soft tissues, RTI, GI infection.