Biliary tract infections, osteomyelitis,burn and wound infections,chlamydial infections, endocarditis, gonorrhea, intra-abdominal infections,nocardiosis, rheumatic fever prophylaxis,sinusitis, eradication of meningococcal carriers, prophylaxis of urinary tract infections, and an alternative agent in the treatment of chancroid. Prevention of bacterial infections in immunosuppressed patients.
Combination inhibits the metabolism of folic acid in bacteria at two different points. Therapeutic Effects:
Bactericidal action against susceptible bacteria. Spectrum:
Active against many strains of gram-positive aerobic pathogens including.
Streptococcus pneumoniae.Staphylococcus aureus.
Group A beta-hemolytic streptococci.
Has activity against many aerobic gram-negative pathogens, such as.
Haemophilusinfluenzae, including ampicillin-resistant strains.
P. carinii (a protozoa).
Not active against
Hypersensitivity to sulfonamides or trimethoprim.
Megaloblastic anemia secondary to folate deficiency.
Severe renal impairment.
Pregnancy, lactation, or children <2 mo (can cause kernicterus in neonates). Use Cautiously In: Impaired hepatic or renal function (dosage reduction required if CCr<30 ml/min).
HIV-positive patients (increased incidence of adverse reactions).
May ↑ half-life,↓ clearance, and exaggerate folic acid deficiency caused by phenytoin.
May ↑ effects of sulfonylurea oral antidiabetics, phenytoin, digoxin, thiopental and warfarin.
May ↑ toxicity of methotrexate.
↑risk of thrombocytopenia from thiazide diuretics (↑ in geriatric patients).
↓efficacy of cyclosporine ( ↓ s serum concentrations) and ↑ risk of nephrotoxicity.
Absorption: Well absorbed from the GI tract. Distribution:Widely distributed. Crosses the blood-brain barrier and placenta and enters breast milk. Metabolism/Excretion: Some metabolism by the liver (20%); remainder excreted unchanged by the kidneys. Half-life: Trimethoprim — 6–11 hr; sulfamethoxazole — 9–12 hr, both prolonged in renal failure.