Sulfonamide

Aka: Sulfonamide, Bactrim, Sulfatrim, Co-trimoxazole, Trimethoprim Sulfamethoxazole, Septra

1. Indications
   1. Urinary Tract Infection
   2. Pneumocystis carinii prophylaxis and treatment
2. Contraindications
   1. Avoid in infant under age 2 months
   2. Sulfonamide allergy
3. Adverse Effects: General
   1. Allergic Reaction or Anaphylaxis
   2. Bone Marrow suppression (Agranulocytosis)
   3. Steven's Johnson Syndrome
   4. Toxic Epidermal Necrolysis
   5. Hyperkalemia
      1. Related to trimethoprim component
      2. Higher risk with underlying renal insufficiency
      3. Exacerbated by ACE Inhibitor, Angiotensin Receptor Blocker, and potassium supplements
4. Adverse Effects: HIV patients (40-60% within 3 weeks)
   1. Hepatitis
   2. Neutropenia
   3. Anemia
   4. Hyponatremia
   5. Nausea or Vomiting
   6. Rash
   7. Fever
5. Precautions
   1. Prolonged use may cause very severe adverse reactions
   2. Follow CBC in prolonged use
6. Preparations
   1. Double Strength (DS)
      1. Trimethoprim 160 mg
      2. Sulfamethoxazole 800 mg
   2. Single Strength (SS)
      1. Trimethoprim 80 mg
      2. Sulfamethoxazole 400 mg
   3. Pediatric Suspension (40/200 per 5 ml)
      1. Trimethoprim 40 mg per 5 ml
      2. Sulfamethoxazole 200 mg per 5 ml
7. Directions (regarding Sulfonamide component)
   1. Take on an empty Stomach
   2. Take more than 1 hour before or two hours after food
8. Dosing: Children (Using 40/200 per 5 ml suspension)
   1. Treatment
      1. Dose 8 mg/kg/day of TMP component PO divided bid
      2. For each 10 kg weight, dose 5 ml suspension bid
      3. Examples
         1. Age 2 months (5 kg): 2.5 cc PO bid
         2. Age 1 year (10 kg): 5.0 cc PO bid
         3. Age 3 years (15 kg): 7.5 cc PO bid
         4. Age 5 years (20 kg): 10 cc PO bid
   2. Prophylaxis of Urinary Tract Infections
      1. Dose: 4 mg/kg/day of Trimethoprim dosed once daily
      2. Avoid use with marked Hyperbilirubinemia
9. Dosing: Adults
   1. Septra one DS tab PO bid
10. Dosing: HIV
    1. Pneumocystis: PO or IV (15 mg/kg of trimethoprim/day)