DBL Sulfamethoxazole & Trimethoprim

Per 5 mL Co-trimoxazole: Sulfamethoxazole (SMZ) 400 mg, trimethoprim (TM) 80 mg

Pre- & post-op infections associated w/ surgery, trauma or gynaecology; septicaemia & other infections due to sensitive organisms eg, typhoid & paratyphoid.

Adult & childn >12 yr Standard dose: 10 mL diluted & infused bd. Severe infections 15 mL diluted & infused bd. Childn ≤12 yr TM 6 mg/kg & SMZ 30 mg/kg daily divided into 2 equal doses, 6-12 yr 5 mL diluted & infused bd, 6 mth-5 yr 2.5 mL diluted & infused bd, 2-5 mth 1.25 mL diluted & infused bd. Pneumocystis carinii pneumonitis TM 20 mg/kg & SMZ 100 mg/kg daily given in equally divided doses every 6 hr for 14 days. CrCl >25 mL/min 1 standard dose every 12 hr for up to 14 days, thereafter ½ standard dose every 12 hr, 15-25 mL/min 1 standard dose every 12 hr for 3 days, thereafter 1 standard dose every 24 hr, <15 mL/min 1 standard dose every 24 hr.

Hypersensitivity to TM or sulfonamides. History of drug-induced immune thrombocytopenia, blood dyscrasias, documented megaloblastic anaemia secondary to folate deficiency. Streptococcal pharyngitis treatment. Concomitant use w/ dofetilide. Marked hepatic damage, severe renal insufficiency. Premature & newborn babies during 1st 8 wk of life.

Discontinue use at 1st appearance of skin rash or any sign of adverse reaction; severe cutaneous adverse reactions eg, SJS, TEN, DRESS, acute generalized exanthematous pustulosis is suspected; haemophagocytic lymphohistiocytosis is diagnosed; preliminary signs of acute resp distress syndrome occurs. Not to be used for group A β-haemolytic streptococcal infections. Acute resp failure, acute eosinophilic pneumonia; thrombocytopenia; Clostridiodes difficile-associated diarrhoea; hypoglycaemia; porphyria or thyroid dysfunction; urinary obstruction, blood dyscrasias, allergies or bronchial asthma; superinfection. AIDS patients; G6PD deficiency; malnutrition; slow acetylators; folate deficiency; phenylalanine metabolism. May cause allergic-type reactions due to Na metabisulfite. Interference w/ Lactobacillus casei serum folate, L leishmanii serum vit B₁₂ & serum MTX assay; Jaffe alkaline picrate reaction assay for creatinine. Ensure adequate fluid intake & maintain urinary output. Monitor electrolytes & renal function, perform CBC & urinalysis w/ microscopic exam during therapy. High-dose & long-term use. Avoid concomitant use w/ leucovorin. Renal dysfunction, hepatic disease. Pregnancy & lactation. Elderly.

Hyperkalaemia. Fungal overgrowth; headache; nausea, diarrhoea; rash.

Increased free MTX levels. Antagonised antibacterial effects w/ PABA or its derivatives. Increased warfarin anticoagulant activity. Increased phenytoin effects & side effects. Potentiated hypoglycaemia w/ sulphonylureas. Increased thrombocytopenia in elderly w/ diuretics. Deteriorated renal function of transplant patients w/ cyclosporin. Megaloblastic anaemia w/ pyrimethamine. Increased plasma digoxin levels. Increased serum K w/ ACE inhibitors, ARBs, K-sparing diuretics, prednisolone. Decreased efficacy of TCAs. Increased sulfamethoxazole blood levels w/ urinary acidifiers, oral anticoagulants, phenylbutazone, oxyphenbutazone, indomethacin. Cross sensitisation w/ antithyroid agents, diuretics (acetazolamide & thiazides), oral hypoglycaemics. Elevated plasma conc of dofetilide. Competitive inhibition w/ drugs forming cations at physiological pH & partly excreted by active renal secretion eg, procainamide, amantadine.

Antibacterial Combinations

J01EE01 - sulfamethoxazole and trimethoprim ; Belongs to the class of combinations of sulfonamides and trimethoprim, including derivatives. Used in the systemic treatment of infections.

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