What are the uses of Septran (sulfamethoxazole and trimethoprim)?

Uses of Septran (Sulfamethoxazole and Trimethoprim)

Septran (sulfamethoxazole and trimethoprim) is primarily indicated for urinary tract infections, acute otitis media, acute exacerbations of chronic bronchitis, shigellosis, Pneumocystis jiroveci pneumonia treatment and prophylaxis, and traveler's diarrhea. 1

Primary Indications

Urinary Tract Infections

• For treatment of UTIs caused by susceptible strains of:
  • Escherichia coli
  • Klebsiella species
  • Enterobacter species
  • Morganella morganii
  • Proteus mirabilis
  • Proteus vulgaris 1
• Recommended for acute uncomplicated cystitis when local resistance is <20% 2
• Standard adult dosage: 160mg TMP/800mg SMX (double strength) twice daily for 3 days 2

Respiratory Tract Infections

• Acute exacerbations of chronic bronchitis in adults due to susceptible strains of:
  • Streptococcus pneumoniae
  • Haemophilus influenzae 1
• Pneumocystis jiroveci pneumonia (PCP):
  • Both treatment and prophylaxis in immunocompromised patients 1
  • Treatment dosage: 15-20 mg/kg/day of TMP component (75-100 mg/kg/day of SMX) divided into 3-4 doses 2
  • Prophylaxis dosage: 150 mg TMP with 750 mg SMX/m² given 3 days per week 2

Gastrointestinal Infections

• Shigellosis: Treatment of enteritis caused by Shigella flexneri and Shigella sonnei 1
• Traveler's diarrhea in adults due to enterotoxigenic E. coli 1
• Recommended for treatment of secretory/invasive traveler's diarrhea (first-line option) 3

Ear Infections

• Acute otitis media in pediatric patients due to susceptible strains of:
  • Streptococcus pneumoniae
  • Haemophilus influenzae 1
• Alternative to amoxicillin for treatment of ear infections in children 2

Special Considerations

Dosing Guidelines

• Adult standard dose: 160mg TMP/800mg SMX (double strength) twice daily 2
• Pediatric dosing: 8-12 mg/kg/day of TMP component (40-60 mg/kg/day of SMX) divided into 2 doses 2
• Renal adjustment:
  • For creatinine clearance 15-30 mL/min: reduce to half the usual dosage
  • For creatinine clearance <15 mL/min: not recommended 2

Contraindications

• Known hypersensitivity to trimethoprim or sulfonamides 2
• Infants younger than 2 months (risk of kernicterus) 2
• Use with caution in patients with G6PD deficiency (risk of hemolytic anemia) 2

Monitoring

• Regular monitoring of complete blood counts, renal function, and liver function during treatment 2
• Watch for signs of hypersensitivity, skin eruptions, and hematologic alterations 2

Antimicrobial Resistance Considerations

• Should be used only to treat infections proven or strongly suspected to be caused by susceptible bacteria 1
• For uncomplicated UTIs, initial episodes should be treated with a single effective agent rather than the combination 1
• Not recommended as first-line for acute uncomplicated cystitis due to rising resistance rates among uropathogens 3
• Should be reserved for important uses other than acute cystitis 3

Adverse Effects

• Common: gastrointestinal symptoms, hypersensitivity reactions 2
• Serious but rare: Stevens-Johnson syndrome, toxic epidermal necrolysis, agranulocytosis, aplastic anemia, hepatic necrosis, and blood dyscrasias 2
• Taking with food may decrease GI side effects 2

Septran has been in clinical use for decades and remains an important antimicrobial option when used appropriately, though increasing bacterial resistance is a concern for its future utility 4.