Sulfonamides (see Table: sulfonamides) are synthetic bacteriostatic antibiotics, which competitively inhibit the conversion of p -aminobenzoic acid in dihydropteroate, need the bacteria for the synthesis of folate, and finally purines and DNA. People do not synthesize folates, but take it on with the food, so that their DNA synthesis is less affected. Sulfonamides sulfacetamide sulfadiazine sulfadoxine sulfamethoxazole sulfanilamide sulfamethizole sulfasalazine sulfisoxazole Two sulfonamides , Sulfisoxazole and sulfamethizole, are available as single agents for oral use. Sulfamethoxazole trimethoprim formulated together with (TMP / SMX trimethoprim and sulfamethoxazole). To the sulfonamides for topical application include silver sulfadiazine, vaginal cream and suppositories with sulfanilamide and ophthalmic sulfacetamide. Pharmacology Most sulfonamides are readily absorbed after oral administration and after topical application for burns. Sulfonamides are distributed throughout the body. They are mainly metabolized by the liver and excreted by the kidneys. Sulfonamides compete for bilirubin binding sites of the albumin. Indications sulfonamides are active against a broad spectrum of gram-positive and many gram-negative bacteria Plasmodium and Toxoplasma spp. Resistances, however, are widespread, and a resistance to a sulfonamide indicates resistance to all. Sulfasalazine can be used orally to treat inflammatory bowel diseases. Sulfonamides are often used in combination with other substances, such. As in nocardiosis, UTI and chloroquine resistant falciparum malaria. Topical sulfonamides can be used to treat the following: burns: silver sulfadiazine and mafenide acetate vaginitis: vaginal cream and suppositories with sulfanilamide superficial eye infections: Ophthalmic sulfacetamide contraindications sulfonamides are common in patients who had an allergic reaction to it or are suffering from porphyria, contraindicated. Sulfonamides can not kill group A streptococci in patients with pharyngitis and should not be used for the treatment of group A streptococcal pharyngitis. Use during pregnancy and lactation Most sulfonamides are in pregnancy category B (animal studies show no risk, human experience is incomplete, or animal studies show risk, but human studies do not). However, the use in women who become mothers in the near future or in nursing mothers is contraindicated, as well as use in patients <2 months (except as adjunctive treatment with pyrimethamine to treat Congenital toxoplasmosis). When these drugs are used during pregnancy or in newborns, this increase the blood levels of conjugated bilirubin and the risk of kernicterus in the fetus or newborn. Sulfonamides occur in breast milk Side effects may be by oral and sometimes also caused by topical sulfonamides; to the side effects include hypersensitivity reactions such as rash, Stevens-Johnson syndrome (Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN)), vasculitis, serum sickness, drug fever, anaphylaxis and angioedema Crystalluria, oliguria and anuria hematologic reactions such as agranulocytosis , thrombocytopenia and in patients with G6PD deficiency, anemia in newborns Kernicterus photosensitivity Neurological effects like insomnia and headache hypothyroidism, hepatitis and activation of latent SLE may occur in patients who are taking sulfonamides occur. These drugs can aggravate porphyria. The incidence of adverse events is different for the various sulfonamides, but cross sensitivities are common. Sulfasalazine intestinal absorption of folate (folic acid) may reduce. Thus, the use of this product may result in folic acid deficiency in patients with inflammatory bowel disease, which also reduces the absorption, especially when food intake is inadequate. Mafenide can carry out the inhibition of carbonic anhydrase metabolic acidosis. Considerations dosage to avoid crystalluria should doctors (to achieve z. B. a urine volume 1200-1500 ml / day), the patient well hydrated. Sulfonamides can be given with renal failure in patients, but it should be determined peak serum levels (<120 ug / ml). Sulfonamides can potentiate sulfonylureas (with the following hypoglycaemia), phenytoin (with increased side effects) and coumarin anticoagulants.