Antimicrobials
Trimethoprim-Sulfamethoxazole (Bactrim, Megatrim)

Trimethoprim-Sulfamethoxazole (Bactrim, Megatrim)

Low
Excellent
IV:$$$ PO:$

General Information

Urinary tract infections, susceptible MRSA infections, Stenotrophomonas infections, Pneumocystis jirovecii pneumonia (treatment or prophylaxis).

Laboratory

  • With high dose: consider baseline and periodic measurement of Cr (dose adjustment and nephrotoxicity assessment)

  • CBC

  • K

  • LFTs

Clinical

  • Hypersensitivity

  • GI effects

  • Nausea
  • Vomiting
  • Hypersensitivity reactions, bone marrow suppression
  • Hyperkalemia
  • Contraindicated in pregnancy and first 4 weeks post-partum if breastfeeding
  • ACEi - increased serum potassium level

  • Increases amantadine levels

  • Decreases cyclosporine

  • Methotrexate - marrow suppression

  • Increases phenytoin

  • Increases rifampin

  • Increases INR with warfarin

Antimicrobial class: Sulfonamide - Antifolate

Average serum half life: 10 hours

Biliary penetration: Moderate

CSF penetration: Therapeutic

Lung penetration: Therapeutic

Urine penetration: Therapeutic