Co-trimoxazole (Trimethoprim + Sulfamethoxazole)

VERBATIM UK SPC §4.2 (CO-TRIMOXAZOLE 80 MG/400 MG TABLETS, PL306840284): 'Adults and children over 12 years STANDARD DOSAGE: 2 tablets every 12 hours'; 'Treatment should be continued until the patient has been symptom free for two days; the majority will require treatment for at least 5 days. If clinical improvement is not evident after 7 days therapy, the patient should be reassessed.'; 'Pneumocystis jirovecii pneumonitis Treatment - Adults and children over 12 years A higher dosage is recommended, using 20 mg trimethoprim and 100 mg sulfamethoxazole per kg of body weight per day in two or more divided doses for two weeks. The aim is to obtain peak plasma or serum levels of trimethoprim of greater than or equal to 5 microgram/ml (verified in patients receiving 1-hour infusions of intravenous Co-Trimoxazole).'; 'Prevention - Adults (>18 years old) The following dose schedules may be used: 160 mg trimethoprim/800 mg sulfamethoxazole daily 7 days per week. 160 mg trimethoprim/800 mg sulfamethoxazole three times per week on alternate days. 320 mg trimethoprim/1600 mg sulfamethoxazole per day in two divided doses three times per week on alternate days.'; 'Nocardiosis - Adults (>18 years old) There is no consensus on the most appropriate dosage. Adult doses of 6 to 8 tablets daily for up to 3 months have been used.'; 'Toxoplasmosis There is no consensus on the most appropriate dosage for the treatment or prophylaxis of this condition. The decision should be based on clinical experience. For prophylaxis, however, the dosages suggested for prevention of Pneumocystis jirovecii pneumonitis may be appropriate.' Elderly: 'Unless otherwise specified standard dosage applies.' §4.1: licensed for treatment and prevention of PJP, treatment and prophylaxis of toxoplasmosis and treatment of nocardiosis; acute uncomplicated urinary tract infection, acute otitis media and acute exacerbation of chronic bronchitis 'may be treated with Co-Trimoxazole where there is bacterial evidence of sensitivity to Co-Trimoxazole and good reason to prefer the combination of antibiotics in Co-Trimoxazole to a single antibiotic'. NO MAXIMUM DOSE is used: a sentence 'The total daily dose should not exceed 320 mg trimethoprim and 1600 mg sulfamethoxazole' sits in the PJP-prevention paragraph after the sentences about children, and the PDF text does not show which population heading it belongs to, so it is not written as a ceiling. SCOPE: THIS SOURCE IS THE ORAL TABLET SPC ONLY. The page's 'Oral or IV' route is covered for ORAL only — no intravenous regimen, no IV PJP dosing (the earlier-fetched eMC product was an intravenous-infusion SPC and was not used) and no UTI-prophylaxis regimen is printed here, so none is given.

As printed in UK SPC §4.2 (standard dosage recommendations for acute infections): 'The standard dosage for children is equivalent to approximately 6 mg trimethoprim and 30 mg sulfamethoxazole per kg body weight per day, given in two equally divided doses.' Both figures are per DAY, not per dose. The SPC prints no age band for this sentence; §4.1 licenses these tablets in 'adults and children over 12 years' and §4.2 says 'No information is available for children aged 12 years and under with renal failure.' The PJP-prevention paragraph repeats the children's sentence and adds a '150 mg trimethoprim/m2/day and 750 mg sulfamethoxazole/m2/day' treatment-day figure, but the PDF text shows no children's heading above it, so that figure is NOT used. Contraindicated in infants during the first 6 weeks of life (§4.3). Verify any under-18 dose against a children's formulary before use.