SULFADIAZINE Drug Interactions: What You Need to Know

Drug Interactions Administration of a sulfonamide may increase the effect of oral anticoagulants and methotrexate, probably by displacement of these drugs from binding sites on plasma albumin. Potentiation of the action of sulfonylurea hypoglycemic agents, thiazide diuretics and uricosuric agents may also be noted. This may also be due to displacement of the drugs from albumin or a pharmacodynamic mechanism may play a role. Conversely, agents such as indomethacin, probenecid and salicylates may displace sulfonamides from plasma albumin and increase the concentrations of free drug in plasma.

CONTRAINDICATIONS Sulfadiazine is contraindicated in the following circumstances: Hypersensitivity to sulfonamides. In infants less than 2 months of age (except as adjunctive therapy with pyrimethamine in the treatment of congenital toxoplasmosis). In pregnancy at term and during the nursing period, because sulfonamides cross the placenta and are excreted in breast milk and may cause kernicterus.

WARNINGS The sulfonamides should not be used for the treatment of group A betahemolytic streptococcal infections. In an established infection, they will not eradicate the streptococcus and, therefore, will not prevent sequelae such as rheumatic fever and glomerulonephritis. Deaths associated with the administration of sulfonamides have been reported from hypersensitivity reactions, agranulocytosis, aplastic anemia and other blood dyscrasias. The presence of such clinical signs as sore throat, fever, pallor, purpura or jaundice may be early indications of serious blood disorders. The frequency of renal complications is considerably lower in patients receiving the more soluble sulfonamides.