Trimethoprim-Sulfamethoxazole DS

General

• Type: Sulfonamide
• Dosage Forms: 160/800
• Common Trade Names: Bactrim DS
• Abbreviations: TMP-SMX, TMP-SMZ

Adult Dosing

General

1 tab (160mg TMP) PO Q12h

PCP Prophylaxis

80-160mg TMP PO daily

PCP Treatment

15-20 mg/kg/day TMP PO divided q6-8h x 21 days

Pediatric Dosing

General (>2mo)

• Mild-mod infection
  • 4-5 mg/kg TMP PO q12hr
• Severe infection
  • 15-20 mg/kg/dy TMP PO divided q6-8h

Contraindications

• Allergy to class/drug
• <2 months of age (except as PCP prophylaxis)
• Significant hepatic impairment
• Megaloblastic anemia or folate deficiency
• G6PD deficiency

Adverse Reactions

Serious

• Stevens-Johnson Syndrome
• Toxic Epidermal Necrolysis
• Fulminant hepatic necrosis
• Agranulocytosis
• Aplastic anemia
• Blood dyscrasias
• Thrombocytopenia
• Hypersensitivity Reaction
• Photosensitivity
• Hepatotoxicity
• Pancreatitis
• Intersitial nephritis
• Renal Failure
• Pulmonary infiltrates
• Myelosuppression
• Methhemoglobinemia
• Hyperkalemia
• Hyponatremia
• Aseptic meningitis
• Seizures
• Lupus Erythematosus
• Hypoglycemia
• Clostridium difficile
• Rhabdomyolysis
• Congenital malformations
• Congenital neural tube defects
• Kernicterus (neonates)

Common

• Nausea and Vomiting
• Anorexia
• Rash
• Urticaria
• Hypersensitivity Reaction
• Photosensitivity
• Diarrhea
• Dizziness
• Dyspepsia
• Headache
• Lethargy

Pharmacology

• Half-life: 6-12h (20-50h ESRD)
• Metabolism:
• Excretion:
• Mechanism of Action: Bactericidal

Special Populations

• Pregnancy: D
• Lactation: ?
• Renal (Adult & Pediatric)
  • CrCl 15-30: Decrease dose by 50%
  • CrCl <15: Avoid use
  • Hemodialysis: Give supplement
  • Peritoneal Dialysis: No supplement
• Hepatic (Adult & Pediatric)
  • Mild-mod impairment: Caution advised
  • Significant impairment: Contraindicated

See Also

• Antibiotics