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are necessary for the synthesis of Aminoacids, hence necessary for bacterialprotein synthesis

growth of micro-organisms

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SulfonamidesSulfadiazine

SulfamethoxazoleSulfisoxazoleSulfamethizole

DiaminopyrimidineTrimethoprim

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Derivatives of sulfanilamidesFirst drug to prevent and cure human

bacterial infection successfullybacteriostatic(stops bacteria fromreproducing)

Structural analogs of para-aminobenzoic acid (PABA)

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MOA: competitively inhibitdihydropteroate synthase

SOA: broad spectrum agents; againstmany gram positive organisms(Streptococcus pyogenes,Streptococcus pneumoniae ) and certaingram negative organism ( Haemophilus

influenzae, Escherichia coli, Proteusmirabilis ) and other strain Chlamydiatrachomatis, Nocardia, Actinomyces,Bacillus anthracis

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Inhibited bySULFONAMIDES Dihydropteroate

synthase

Dihydrofolate

reductase

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INDICATION: Often used to treat urinary tract

infections(E. coli) including acute andchronic cystitis, and chronic upper UTITx for nocardiosis, trachoma, inclusionconjunctivitis and dermatitis herpetiformis

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Sulfadiazine + Pyrimethamine tx oftoxoplasmosis

Px should take 2liters fluid to avoid UTcomplicationPyrimethamine: Ldose=75mg; 25mg

daily& Sulfadiazine= 1g/every 6 hours; for3-6 wks

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Cotrimoxazole*=Sulfamethoxazole +Trimethoprim

Tx for Pneumocystis carinii pneumonia,Shigella enteritis, Serratia sepsis, UTI*,respiratory infections, gonococcalurethritisDOC for Stenotrophomonas maltophiliaIncreased frequency of Cutaneoushypersensitivity for AIDS Px

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Sulfisoxazole + Erythromycin = AcuteOtitis Media ( H. Influenzae)

Sulfisoxazole + Phenazopyridine =uncomplicated UTI (relief of Sx of pain,

burning, urgency)

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Prophylactic sulfonamide therapy toprevent Streptococcal infections andrheumatic fever recurrences

PRECAUTIONS:May cause blood dyscrasias (HemolyticAnemia)

For Px w/ G6PD deficiency, AplasticAnemia, Thrombocytopenia,Agranulocytosis, Eosinophilia

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Life Threatening Hepatitis Caused by drug toxicity (rare SE) Headache, nausea, vomiting, jaundice

Hypersensitivity (manifest in skin&mucous membranes)

skin rashexfoliative dermatitisphotosensitivity

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Trimethoprim

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Substituted pyrimidineCommonly combined withsulfamethoxazole

MOA: Inhibits dihydrofolate reductasethus blocking bacterial folic acidsynthesis

SOA: most gram negative and grampositive microorganism

*If used alone may develop resistance

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SOA: Streptococcus pneumoniae,Neisseria meningitidis,

Corynebacterium diphtheriae ; somestrains of Staphylococcus aureus,Staphylococcus epidermidis, Proteusmirabilis, Enterobacter, Salmonella,Shigella, Serratia, Klebsiella andEscherichia coli

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Inhibited byTRIMETHOPRIM

Dihydropteroatesynthase

Dihydrofolate

reductase

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INDICATION:Tx for UTI caused by E. coli, P. mirabilis,Klebsiella and Enterobacter

Tx for acute gonococcal urethritis, acuteexacerbation of chronic bronchitis,shigellosis, and Salmonella infections

Prophylactic/Suppressive therapy for P.Carinii pneumoniaDOC for Stenotrophomonas maltophiliainfections

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PRECAUTIONSSkin sensitization (rash, pruritus,exfoliative dermatitis)Blood dyscrasia(rarely)Adverse GI effect(nausea, vomiting,epigastric distress glossitis)Neonate may develop kernicterusAIDs Px may suffer from fever, rash,malaise, pancytopenia