Sulfonamides類抗生素
Treatment of urinary tract infections caused by susceptible strains of E. coli, Proteus (indole positive or negative), Klebsiella, Enterobacter, H. influenzae, S. pneumoniae, Shigella spp.

Antibiotic, Miscellaneous; Antibiotic, Sulfonamide Derivative
1. Sulfamethoxazole: interferes with bacterial folic acid synthesis and growth via inhibition of dihydrofolic acid formation from para-aminobenzoic acid
2. Trimethoprim: inhibits dihydrofolic acid reduction to tetrahydrofolate resulting in sequential inhibition of enzymes of the folic acid pathway

1. Pregnancy, infants younger than 2 months, lactation.
2. Hypersensitivity to sulfonamides or trimethoprim, patients with impaired renal or hepatic function.

Probably safe, except in premature infant or infant with G6PD deficiency.

Agranulocytosis, aplastic and megaloblastic anemia, nausea, erythema multiforme, headache, and mental depression.

2 tab Q12H for 10-14 days in urinary tract infection; MAX trimethoprin 640mg, sulfamethoxazole 3.2g

8 mg/kg trimethoprim and 40 mg/kg sulfamethoxazole daily, give in 2 divided dose Q12H

1. Ccr >30 mL/minute: standard dose
2. Ccr 15-30 mL/minute: half the standard dose
3. Ccr below 15 mL/minute: not recommended