Poorly Absorbed Sulfonamides

Sulfasalazine (azulfidine) is very poorly absorbed from the GI tract and is used in the therapy of ulcerative colitis and Crohn's disease (see Chapter 38).


Sulfacetamide is the N1-acetyl-substituted derivative of sulfanilamide. Its aqueous solubility is ~90 times that of sulfadiazine. This drug (isopto-cetamide, others) is employed extensively for ophthalmic infections. Very high aqueous concentrations are not irritating to the eye and are effective against susceptible microorganisms. The drug penetrates readily into ocular fluids and tissues. Sensitivity reactions to sulfacetamide are rare, but it should not be used in patients with known sulfonamide hypersensitivity.

Silver Sulfadiazine

Silver sulfadiazine (silvadene, others) inhibits the growth of nearly all pathogenic bacteria and fungi, including some species resistant to sulfonamides. The compound is used topically to reduce microbial colonization and the incidence of infections in burn patients. It is not used to treat an established deep infection. Silver is released slowly in concentrations that are selectively toxic to microorganisms. However, bacteria may develop resistance to silver sulfadiazine. The plasma concentration of sulfadiazine may approach therapeutic levels if a large surface area is involved. Adverse reactions—burning, rash, and itching—are infrequent. Silver sulfadiazine is considered one of the agents of choice for the prevention of burn infection.


This sulfonamide (a-amino-p-toluene-sulfonamide) is marketed as mafenide acetate (sulfamy-lon). It is used topically to prevent colonization of burns by a large variety of gram-negative and gram-positive bacteria. it is associated with significant adverse effects, including intense pain at sites of application, allergic reactions, loss of fluid by evaporation from the burn surface, and metabolic acidosis secondary to inhibition of carbonic anhydrase.

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  • may
    Why poorly absorb sulphonamide?
    2 years ago
  • Tomacca Bolger-Baggins
    Where does sulphonamide absorbed?
    2 years ago

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