Essay on Sulfonamides


Sulfonamides are a group of artificial drugs possessing the sulfonamide chemical group. They can also be referred to as sulfa drugs. Some of the drugs classified as sulfonamides include sulfadiazine, sulfamethizole, sulfamethoxazole, sulfasalazine and sulfisoxazole.

Essay on Sulfonamides


Sulfonamides are mainly indicated for use in urinary tract infections, conjunctivitis and toxoplasmosis.

They can also be used in the prevention and treatment of burn related infections and in combination with pyrimethamine for used in treatment of malaria.


A majority of sulfonamides are taken through the oral route where they are readily absorbed. Those used in treatment and prevention of burn related infections are applied topically. On administration, sulfonamides are distributed throughout the body. Metabolism is primarily done by the liver after which they are excreted via the kidneys. Sulfonamides actively compete for bilirubin binding sites on albumin.

Mechanism of action and resistance

Sulfonamides are artificial bacteriostatic antibiotics. They work primarily through inhibition of the conversion of p-aminobenzoic acid to dihydropteroate. Dihydropteroate in bacteria is required in the synthesis of folate which is consequently essential in the synthesis of both purine and DNA. Resistance to sulfonamides is usually widespread with the resistance towards one sulfonamide indicating resistance to almost all.

Adverse effects

Some of the commonest adverse reactions include hypersensitivity reactions which include the appearance of rashes, vasculitis, serum sickness, drug fever, anaphylaxis and angioedema. The patient may also experience crystalluria, oliguria and anuria. Haematologic adverse effects may also be observed. These include agranulocytosis and thrombocytopenia. Haemolytic anaemia may be observed in people deficient of glucose-6-phosphate dehydrogenase. Photosensitivity is another commonly observed side effects. Patients may also complain of occasional headaches and insomnia. Hepatitis and hypothyroidism may also be observed in people taking sulfonamides and especially in continued long-term use of the drugs.