Dose Adult - Dosage Range
Oral
Adults: Loading dose 2–4 g, followed by 1–1.5 g every 6 hours depending on indication. For toxoplasmosis: used with pyrimethamine plus folinic acid for several weeks.
Paediatric: 75 mg/kg loading dose followed by 100–150 mg/kg/day in divided doses. Dose varies according to indication.
Brands; See below
Combinations;
Frequently combined with pyrimethamine and folinic acid for toxoplasmosis. Topical silver sulfadiazine is a separate preparation used for burns.
Indications; Toxoplasmosis, nocardiosis (alternative regimen), susceptible urinary tract infections, rheumatic fever prophylaxis (historical), and other susceptible bacterial infections.
Precautions; Maintain adequate hydration. Monitor CBC, renal and hepatic function during prolonged therapy.
Contraindications; Sulfonamide hypersensitivity, severe hepatic disease, severe renal impairment without monitoring, infants under 2 months, megaloblastic anaemia due to folate deficiency.
Pregnancy/Lactation; Avoid near term and during breastfeeding of premature or jaundiced infants. Use only when benefits outweigh risks.
| MOA | Competitive inhibition of dihydropteroate synthase, blocking bacterial folic acid synthesis and inhibiting nucleic acid production. |
|---|---|
| Uses | Toxoplasmosis (with pyrimethamine), susceptible bacterial infections, nocardiosis, selected urinary tract infections. |
| Side Effects | Rash, nausea, vomiting, crystalluria, photosensitivity, Stevens-Johnson syndrome, toxic epidermal necrolysis, hepatitis, bone marrow suppression. |
| Polypharmacy | May increase effects of warfarin, methotrexate, sulfonylureas and phenytoin. Increased risk of bone marrow toxicity with pyrimethamine unless folinic acid is given. |
| Drug Category | DRUGS ACTING ON INFECTIONS |
| Drug Sub-Category | Sulfonamide Antibacterial |
| Brand Name | Manufacturer Name | Distributor | Drug Strength | Packaging | Formulation | Formulation Strength | Approx. Price |
|---|---|---|---|---|---|---|---|
| Sulfadiazine Generic | Various | Special Order | 500 mg | 100 | Tablet | per tablet | KES 2,500–5,000 |
| Sulfadiazine Generic | Various | Hospital Supply | 500 mg | 10 | Tablet | per tablet | KES 300–700 |
| Daraprim + Sulfadiazine* | Various | Hospital Supply | Variable | Treatment Pack | Combination Therapy | Used with folinic acid | Hospital procurement |
*Pyrimethamine (Daraprim) and sulfadiazine are supplied separately but are routinely prescribed together for toxoplasmosis.