Formulary
Co-trimoxazole: Indications, Dosing, Side Effects and Interactions
For co-trimoxazole Sulfamethoxazole and trimethoprim are used in combination (as co-trimoxazole) because of their synergistic activity (the importance of the...
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Co-trimoxazole: Indications, Dosing, Side Effects and Interactions
For co-trimoxazole Sulfamethoxazole and trimethoprim are used in combination (as co-trimoxazole) because of their synergistic activity (the importance of the...
Drug action
For co-trimoxazole Sulfamethoxazole and trimethoprim are used in combination (as co-trimoxazole) because of their synergistic activity (the importance of the sulfonamides has decreased as a result of increasing bacterial resistance and their replacement by antibacterials which are generally more active and less toxic).
Indications and dose
**Treatment of susceptible infections**
- **Child** (By Mouth): 12-17 years 960 mg twice daily.
- **Adult** (By Mouth): 960 mg twice daily.
- **Adult** (By Intravenous Infusion): 960 mg every 12 hours, increased to 1.44 g every 12 hours, increased dose used in severe infection.
**Moderate diabetic foot infection,Severe diabetic foot infection**
- **Adult** (By Mouth): 960 mg twice daily.
- **Adult** (By Intravenous Infusion): 960 mg every 12 hours, increased if necessary to 1.44 g every 12 hours.
**Leg ulcer infection**
- **Adult** (By Mouth): 960 mg twice daily for 7 days.
- **Adult** (By Intravenous Infusion): 960 mg every 12 hours, increased to 1.44 g every 12 hours, increased dose used in severe infection.
**Hospital-acquired pneumonia**
- **Adult** (By Mouth): 960 mg twice daily for 5 days then review.
**Acute exacerbation of chronic obstructive pulmonary disease**
- **Adult** (By Mouth): 960 mg twice daily for 5 days.
- **Adult** (By Intravenous Infusion): 960 mg every 12 hours, increased if necessary to 1.44 g every 12 hours, increased dose used in severe infection.
**Treatment ofPneumocystis jirovecii(Pneumocystis carinii) infections (undertaken where facilities**
- **Child** (By Mouth, Or By Intravenous Infusion): Treatment of Pneumocystis jirovecii ( Pneumocystis carinii ) infections (undertaken where facilities for appropriate monitoring available-consult microbiologist and product literature) 120 mg/kg daily in 2-4 divided doses for 14-21 days, oral route preferred for children.
- **Adult** (By Mouth, Or By Intravenous Infusion): 120 mg/kg daily in 2-4 divided doses for 14-21 days.
**Prophylaxis ofPneumocystis jirovecii(Pneumocystis carinii) infections**
- **Child** (By Mouth): Prophylaxis of Pneumocystis jirovecii ( Pneumocystis carinii ) infections 450 mg/m 2 twice daily (max. per dose 960 mg) for 3 days of the week (either consecutively or on alternate days), dose regimens may vary, consult local guidelines.
- **Adult** (By Mouth): 960 mg once daily, dose reduced if not tolerated to 480 mg once daily, alternatively 960 mg once daily on alternate days, to be given on 3 days of the week, alternatively 960 mg twice a day on alternate days, to be given on 3 days of the week.
**Acute prostatitis (initiated under specialist supervision)**
- **Adult** (By Mouth): 960 mg twice daily for 14 or 28 days based on clinical assessment.
**Treatment of susceptible infections for co-trimoxazole**
- **Child 6 weeks-5 months** (By mouth): 120 mg twice daily, alternatively 24 mg/kg twice daily.
- **Child 6 months-5 years** (By mouth): 240 mg twice daily, alternatively 24 mg/kg twice daily.
- **Child 6-11 years** (By mouth): 480 mg twice daily, alternatively 24 mg/kg twice daily (max. per dose 960 mg).
- **Child 12-17 years** (By mouth): 960 mg twice daily.
- **Child 6 weeks-5 years** (By intravenous infusion): 18 mg/kg every 12 hours; increased to 27 mg/kg every 12 hours, increased dose used in severe infection.
- **Child 6-17 years** (By intravenous infusion): 18 mg/kg every 12 hours (max. per dose 960 mg); increased to 27 mg/kg every 12 hours (max. per dose 1.44 g), increased dose used in severe infection.
**Prophylaxis of infection from human bites, Prophylaxis of infection from animal bites for co-trimoxazole**
- **Child 6 weeks-5 months** (By mouth): 120 mg twice daily for 3 days, alternatively 24 mg/kg twice daily for 3 days.
- **Child 6 months-5 years** (By mouth): 240 mg twice daily for 3 days, alternatively 24 mg/kg twice daily for 3 days.
- **Child 6-11 years** (By mouth): 480 mg twice daily for 3 days, alternatively 24 mg/kg twice daily (max. per dose 960 mg) for 3 days.
**Treatment of infection from human bites, Treatment of infection from animal bites for co-trimoxazole**
- **Child 6 weeks-5 months** (By mouth): 120 mg twice daily for 5-7 days, alternatively 24 mg/kg twice daily for 5-7 days.
- **Child 6 months-5 years** (By mouth): 240 mg twice daily for 5-7 days, alternatively 24 mg/kg twice daily for 5-7 days.
- **Child 6-11 years** (By mouth): 480 mg twice daily for 5-7 days, alternatively 24 mg/kg twice daily (max. per dose 960 mg) for 5-7 days.
**Treatment of Pneumocystis jirovecii (Pneumocystis carinii) infections (undertaken where facilities for appropriate monitoring available-consult microbiologist and product literature) for co-trimoxazole**
- **Child** (By mouth, or by intravenous infusion): 120 mg/kg daily in 2-4 divided doses for 14-21 days, oral route preferred for children.
**Prophylaxis of Pneumocystis jirovecii (Pneumocystis carinii) infections for co-trimoxazole**
- **Child** (By mouth): 450 mg/m2 twice daily (max. per dose 960 mg) for 3 days of the week (either consecutively or on alternate days), dose regimens may vary, consult local guidelines.
Cautions
For co-trimoxazole Asthma; avoid in blood disorders (unless under specialist supervision); avoid in infants under 6 weeks (except for treatment or prophylaxis of pneumocystis pneumonia) because of the risk of kernicterus; elderly (increased risk of serious side-effects) (in adults); G6PD deficiency (risk of haemolytic anaemia); maintain adequate fluid intake; predisposition to folate deficiency; predisposition to hyperkalaemia
Contraindications
For co-trimoxazole Acute porphyrias
Side effects
For co-trimoxazole Common or very common Diarrhoea; electrolyte imbalance; fungal overgrowth; headache; nausea; skin reactions Uncommon Vomiting Rare or very rare Agranulocytosis; angioedema; aplastic anaemia; appetite decreased; arthralgia; ataxia; cough; depression; dizziness; dyspnoea; eosinophilia; fever; haemolysis; haemolytic anaemia; hallucination; hepatic disorders; hypoglycaemia; leucopenia; megaloblastic anaemia; meningitis aseptic; metabolic acidosis; methaemoglobinaemia; myalgia; myocarditis allergic; nephritis tubulointerstitial; neutropenia; oral disorders; pancreatitis; peripheral neuropathy; photosensitivity reaction; pseudomembranous enterocolitis; renal impairment; renal tubular acidosis; respiratory disorders; rhabdomyolysis; seizure; serum sickness; severe cutaneous adverse reactions (SCARs); systemic lupus erythematosus (SLE); thrombocytopenia; tinnitus; uveitis; vasculitis; vertigo Frequency not known Haemophagocytic lymphohistiocytosis; psychotic disorder Side-effects, further information Co-trimoxazole is associated with rare but serious side effects. Discontinue immediately if blood disorders (including leucopenia, thrombocytopenia, megaloblastic anaemia, eosinophilia, haemophagocytic lymphohistiocytosis) or rash/skin reactions (including Stevens-Johnson syndrome, toxic epidermal necrolysis, acute generalised exanthematous pustulosis, drug reaction with eosinophilia and systemic symptoms) develop.
Pregnancy
For co-trimoxazole Teratogenic risk in first trimester (trimethoprim a folate antagonist). Neonatal haemolysis and methaemoglobinaemia in third trimester; fear of increased risk of kernicterus in neonates appears to be unfounded.
Breast feeding
For co-trimoxazole Small risk of kernicterus in jaundiced infants and of haemolysis in G6PD-deficient infants (due to sulfamethoxazole).
Hepatic impairment
For co-trimoxazole Manufacturer advises avoid in severe liver disease.
Renal impairment
For co-trimoxazole Avoid if creatinine clearance less than 15 mL/minute or in severe insufficiency where plasma-sulfamethoxazole concentration cannot be monitored. M Monitor plasma-sulfamethoxazole concentrations (consult product literature). M Dose adjustments See Prescribing in renal impairment . In adults: Use half normal dose if creatinine clearance 15-30 mL/minute. M In children: Use half normal dose if creatinine clearance 15-30 mL/minute (consult product literature). M
Medicinal forms
Tablet,Suspension,Solution
Clinical governance
**Author:** MedNext Clinical Team. **Clinical reviewer:** Dr Shameer Deen, MBBS, MS, MRCS. **Sources:** BNF, Indian Pharmacopoeia, CIMS India. **Correction:** Report errors at support@mednext.academy.
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