Skip to content
Disclaimer to the On-line Edition
This Manual has been designed for use in the NICU at London Health Sciences Centre (LHSC), London, Ontario, Canada, and represents clinical practice at this institution. The information contained within the Manual may not be applicable to other centres. If users of this Manual are not familiar with a drug, it is recommended that the official monograph be consulted before it is prescribed and administered. Any user of this information is advised that the contributors, Editor and LHSC are not responsible for any errors or omissions, and / or any consequences arising from the use of the information in this Manual.

CO-TRIMOXAZOLE
(Trimethoprim - Sulfamethoxazole)

Indication

  • there are few indications for the use of co-trimoxazole in the neonate; co-trimoxazole is CONTRAINDICATED DURING THE FIRST 7 DAYS OF LIFE due to risk of kernicterus at lower levels of bilirubin
  • its use is limited to those unusual situations where culture and sensitivity results dictate (eg. Pneumocystis carinii).

Pharmacology

  • co-trimoxazole is a combination product which contains two anti-infectives, trimethoprim (TMP) and sulfamethoxazole (SMZ) in a 1:5 ratio.
  • co-trimoxazole acts by inhibiting sequential steps in the synthesis of tetrahydrofolic acid, an important cofactor in DNA synthesis.
  • well absorbed (90 to 100%) following oral administration.
  • in adults, approximately 80% of trimethoprim and 20% of sulfamethoxazole are excreted unchanged in the urine.

Side Effects

  • sulfamethazole weakly displaces bilirubin from albumin; do NOT administer co-trimoxazole to infants with hyperbilirubinemia.
  • GI adverse effects and sensitivity skin reactions are the most frequent (approx 3.5% of patients).
  • rare hematological reactions.
  • local reactions (pain, inflammation and rarely thrombophlebitis).

Contraindications

  • patients with documented megaloblastic anemia secondary to folate deficiency.
  • patients with suspected glucose-6-phosphate-dehydrogenase (G-6-PD) deficiency
  • use within first 7 days of life

Dose

  • for infections caused by Pneumocystic carinii

    TMP 5 mg/kg IV Q6H
    SMX 25 mg/kg IV Q6H

  • for infections caused by other organisms

    TMP 2.5 to 5 mg/kg IV, po Q12H
    SMX 12.5 to 25 mg/kg IV, po Q12H

  • the available IV solution must be DILUTED at least 15 times prior to administration and given by slow infusion over at least 30 minutes.

    IT SHOULD BE NOTED BY THE PHYSICIAN THAT THE MANUFACTURER STATES THAT CO-TRIMOXAZOLE MUST BE DILUTED AT LEAST 15 TIMES BEFORE ADMINISTRATION. CONSIDERATION SHOULD BE GIVEN TO THE USE OF A THIRD GENERATION CEPHALOSPORIN BEFORE CO-TRIMOXAZOLE IS USED. CO-TRIMOXAZOLE SHOULD NOT BE USED IN INFANTS LESS THAN 28 DAYS OLD. IT IS RECOMMENDED THAT THIS GUIDELINE BE ADHERED TO. THE PHYSICIAN SHOULD BE AWARE OF THE INCREASED FLUID INTAKE AND ADJUST THE FLUID MANAGEMENT (including TPN) OF THE INFANT ACCORDINGLY.

  • Sample Calculation for IV administration. Order reads:
    6mg TMP and 30 mg SMZ IV q12h

    desired dose
    available dose
    xavailable volume
    = TMP6 mg
    16 mg
    x1 mL=0.375 mL drug
    = SMZ30 mg
    80 mg
    x1 mL=0.375 mL drug

    Therefore the volume of drug to be administered is 0.375 mL

    Diluted 15 times

    0.375 mL x 15 = 5.625 mL

    Total Volume

    0.375 mL (Drug) + 5.25 mL (Diluent) = 5.625 mL (Round off to 5.6 mL) to be given by slow infusion over 30 minutes

    * Remember: whenever a drug volume exceeds 2 mL, additional extension tubing must be added.

    Available

    • the pediatric Suspension contains per mL:8 mg TMP
       40 mg SMX
    • 5 mL multidose vial for injection, with benzyl alcohol present, contains per mL:
      16 mg TMP
      80 mg SMX
    • the multidose vial, and the following directions, will be supplied by the Pharmacy Department:


      BABY: _________________ NICU
      (16MG/ML TRIMETHOPRIM &
      80MG/ML SULFAMETHOXAZOLE)
      ________ MG TRIMETHOPRIM +
      ________ MG SULFAMETHOXAZOLE =
      ________ ML
      MUST BE FURTHER DILUTED 15 TIMES
      BEFORE ADMINISTRATION.
      ________ ML CO-TRIMOXAZOLE +
      ________ ML NORMAL SALINE/D5W =
      ________ ML.
      IV Q ________H DATE:_______

References

  1. McEvoy G K (ed): AHFS Drug Information, American Society of Hospital Pharmacists, 1991.
  2. Roberts, RJ: Drug Therapy in Infants, W.B. Saunders, Toronto, 1984.
  3. Fanaroff AA and Martin RJ (eds): Neonatal-Perinatal Medicine, Mosley, Toronto, 1992.



Last Uploaded: Thursday, 26-May-2011 00:53:29 EDT
About Us Patients, Families & Visitors For Health Professionals Careers Research & Training Ways to Give
LHSC Maps & Directions Programs & Services Media Room Contact Us For Our Employees Privacy Statement Terms & Conditions