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6 Cards in this Set
- Front
- Back
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Trimethoprim
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- inhibits DHFR (converts FH2 to FH4)
- when given by itself = static effect Resistance - overproduction of DHFR - production of altered reductase with decreased drug binding - reduced cell permeability PK - more lipid soluble - given in 5:1 (sulfa: trimeth) - excreted via the kidneys - concentrates in prostatic and vaginal fluids (more acidic) - widely distributed (CNS) Spectrum of Action - treatment of UTI - effective against staph aureus, haemophilus, moraxella Adverse Rxns - skin problems (increased with HIV and combo) - hepatologic problem (anemias, leukopenia, thrombocytopenia, granulocytopenia) |
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Sulfonamides
MOA & Resistance |
- to be active must have sulfur linked to benzene ring and amino group in para position
- weak acids MOA - must synthesize folate from PABA - inhibit dihydropteroate synthase --> inhibits folate production Resistance - overproduction of PABA - impair permeability of sulfonamide (decrease cell uptake) - production of folic-acid synthesizing enzyme with low affinity for sulfonalmide |
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Sulfonamides
Spectrum of Action & PK |
- Gram (+) and (-)
- nocardia (infections of the lungs, skin, brain) - UTI - Treatment of toxoplasmosis (lymph nodes) - treatment of infections caused by pneumycosis which causes pneomonia - Kidney excretion = decrease dose with renal disease |
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Sulfonamides
Adverse Reactions |
- Hypersensitivity = edema, skin rash, Stevens Johnson Syndrome, photosensitivity, n/v/d
- Hematopoetic disturbances (bone marrow) = problems with blood cells, anemias (as a result of sensitization or glucose 6- phosphate dehydrogenase - Kernicterus during 3rd trimester = sulfonamides displace bilirubin = increased free bilirubin = decreased brain development - Urinary Tract Disturbances - as urine is more acidic = sulfonamides are less ionized = less soluble = more likely to precipitate out of urine - keep patient hydrated - alkaline the urine by adding bicarbonate -sulfadiazine, sulfamethoxazole = less soluble |
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Quinolones
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- DNA Gyrase inhibitors
- active against gram (+) and (-) - prevent relaxation of positively supercoiled DNA - Cipro = greatest activity against gram - - Levofloxaxin = greatest activity against gram + Resistance - Qnr proteins = decrease quinolone binding - Acetylation = modify cipro - mutations in quinolone binding region - cross-resistance Spectrum of Action - broad spectrum - UTI - infections associated with GI and respiratory tracts - Resistant TB PK - administered orally - absorption decreased by presence of divalent cations - renally excreted = dose adjustment Adverse Rxns - well tolerated - nausea, vomiting, diarrhea - not recommended in children <18 (damage to cartilidge |
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Nitrofurantoin
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- static effect
- treats UTIs - short 1/2 life Adverse Reactions - hemolytic anemia --> G-6-PDH deficient - chronic treatment (>6 mons) = pulmonary fibrosis |
