Sulphadimidine
Indications
Sulphadimidine is used for:
UTI
Adult Dose
Oral
Susceptible infections
Adult: Initially, 2 g then 0.5-1 g every 6-8 hr.
Hepatic impairment: Dose reduction may be needed. Severe: Contraindicated.
Child Dose
Renal Dose
Renal impairment: Dose reduction may be needed. Severe: Contraindicated.
Administration
Contra Indications
Severe renal or hepatic failure; blood disorders; hypersensitivity to sulfonamides; acute porphyria; SLE. Pregnancy (3rd trimester) and lactation; infants ?2 mth.
Precautions
Renal or hepatic impairment; history of allergy or asthma; AIDS; G6PD deficiency; elderly; ensure adequate fluid intake to reduce risk of crystalluria.
Pregnancy-Lactation
Interactions
Potentiates effects of oral anticoagulants, methotrexate, phenytoin. Compounds that render the urine acidic increase risk of crystalluria.
Potentially Fatal: Increased blood dyscrasias with clozapine
Adverse Effects
Side effects of Sulphadimidine :
Nausea, vomiting, anorexia, diarrhoea, hypersensitivity reactions, SLE, serum sickness-like syndrome, liver necrosis and hepatomegaly, myocarditis, pulmonary eosinophilia and fibrosing alveolitis, vasculitis, hypoglycaemia, hypothyroidism, neurological reactions, jaundice and kernicterus in premature neonates. Pseudomembranous colitis.
Potentially Fatal: Stevens-Johnson syndrome; toxic epidermal necrolysis; blood dyscrasias; anaphylaxis.
Mechanism of Action
Sulfadimidine is a short-acting sulfonamide. It interferes with the synthesis of nucleic acids in sensitive organisms by blocking the conversion of p-aminobenzoic acid (PABA) to the co-enzyme dihydrofolic acid. Its action is bacteriostatic, although it exerts bactericidal effects where concentrations of thymine are low in the surrounding medium. It has been used with other sulfonamides, e.g. sulfamerazine and sulfadiazine. In veterinary medicine, it is sometimes used with baquiloprim or trimethoprim. Sulfadimidine is used to determine acetylator status due to its pharmacokinetic differences in fast and slow acetylators.