Adult

Co-trimoxazole

General Information

Formulary antimicrobial: Use in accordance with Trust guidelines 

AWaRe antibiotic classification: 'Access'. Use as per guidelines.

  • 480 mg of co-trimoxazole consists of sulfamethoxazole 400 mg and trimethoprim 80 mg (ratio 5:1)
  • Doses throughout Trust adult antimicrobial guidelines are expressed as the total quantity of trimethoprim and sulfamethoxazole.

See Trust Safety Message for Prescription of co-trimoxazole for action points when prescribing co-trimoxazole.

Dosing

 

Oral

 co-trimoxazole dose

Intravenous

co-trimoxazole dose

Standard dose

960mg BD

Stenotrophomonas maltophilia (or other organisms on advice of Micro/ID only)

960mg TDS

Pneumocystis jirovecii Pneumonia (PJP - formerly PCP)

See Pneumocystis jirovecii pneumonia (PJP)

For dosing in renal impairment see below

Obesity

Non-PCP indications:

  • There is no consensus on dosing in obesity. If body weight is over 120kg considered increasing to 960mg tds, particularly in patients with severe infections, considering patient’s renal function.

PCP:

  • Use adjusted bodyweight (AdjBW) if obese (BMI 30 or more).

Renal and hepatic impairment

Renal impairment

For all indications, including PCP

eGFR (mL/min/1.73m2)

Oral

Intravenous

More than 30

No adjustment

15-30

Half normal dose

Less than 15

Discuss with Micro/ID/pharmacy. Ideally, haemodialysis facilities should be available

 

Hepatic impairment
Avoid in severe hepatic impairment

Monitoring

Monitor:

  • U+Es daily. Risk of Acute kidney injury / hyperkalaemia. Risk factors are:
    • age over 65 years old
    • Chronic Kidney Disease
    • current AKI
    • current hyperkalaemia and/or hyponatraemia
    • concurrent use of ACEi, ARBs or potassium-sparing diuretics (temporary dose adjustment or cessation of these drugs may be warranted, depending on indications)
  • Monitor FBC regularly. Risk of Myelosuppression, agranulocytosis, aplastic anaemia, other blood dyscrasias.
  • Monitor LFTs regularly. 

Notable interactions

There are multiple interactions between co-trimoxazole and other medications. Ensure interactions are checked with the BNF and SPC. Discussion with a pharmacist is advised.

Pregnancy and breastfeeding

Pregnancy 

  • Discuss with pharmacy.

Breastfeeding

  • Discuss with pharmacy. Risk of kernicterus and haemolysis. Avoid in known G6PD deficiency, hyperbilirubinaemia and in jaundiced infants.

Additional information

  • Haemolysis may occur in patients with G6PD deficiency
  • Contraindicated in acute porphyria. See Acute Porphyria
  • Co-trimoxazole has excellent bioavailability and should only be given if NBM, poor enteral absorption or as per guidance for severe infections.
  • Where appropriate see Co-trimoxazole desensitisation guideline.

References

Editorial Information

Next review date: 01 Feb 2028