Drug Characteristics
  • Formulation

    Tablets : 480 mg, 960 mg, Suspension: 240 mg/5 mL, 480 mg/5 mL

    Injection : 480 mg/5 mL        

  • Dose

    Moderate to severe PCP

    Intravenous trimethoprim 20 mg/kg and sulphamethoxazole

    100 mg/kg in 3–4 divided doses for 3 days then reduce to trimethoprim

    15 mg/kg and 75 mg/kg sulphamethoxazole every 24 h in 2–3 divided doses for 18 further days

    Mild to moderate PCP

    1920 mg (2 _ 960 mg tablets) orally TDS for 21 days OR Intravenous

    Trimethoprim 15 mg/kg and 75 mg/kg sulphamethoxazole every 24 hours in 3 divided doses for 21 days.

    Primary PCP or toxoplasmosis prophylaxis

    adult 480-960 mg orally

    infant 900 mg/m2 once daily Mon/Wed/Fri

    <6 months: 120 mg once daily Mon/Wed/Fri

    6–12 months: 240 mg once daily Mon/Wed/Fri

    Secondary PCP prophylaxis

    960 mg three times a week.

    Toxoplasmosis treatment (3 rd line)

    60 mg/kg/day in 3 divided doses       

  • Side Effects

    Rash (Stevens–Johnson syndrome: rare), nausea and vomiting, neutropenia, anaemia, abnormal LFTs, impaired renal function (at high doses), pancreatitis, hyperkalaemia, haemolysis in glucose-6-phosphate dehydrogenase (G6PD) deficiency. Cotrimoxazole desensitization

  • Interactions

    Additive toxicity with bone marrow suppressive agents e.g. ganciclovir, zidovudine

    Warfarin effect enhanced

    Effect of sulphonylureas enhanced

    Phenytoin – anti-folate effect and plasma concentration increased

    Ciclosporin – increased risk of nephrotoxicity

    Additive toxicity with other sulphonamides – (caution: co-trimoxazole and sulfadiazine should not be co-prescribed)        

  • Renal

    Seek specialist advice from HIV pharmacist

    GFR 30–50: Dose as in normal renal function

    GFR 15–30: 60 mg/kg/day in 2 divided doses

    GFR <15: Not recommended        

  • Hepatic

    Intravenous sulphamethoxazole is contra-indicated in patients showing marked parenchymal damage

  • Pregnancy

    Human Data Suggest Risk in 3rd Trimester

  • Other Information