Which medications in the drug class Sulfonamide are used in the treatment of Toxoplasmosis?

Updated: Mar 08, 2019
  • Author: Murat Hökelek, MD, PhD; Chief Editor: Michael Stuart Bronze, MD  more...
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Answer

Sulfonamide

These agents exert bacteriostatic action through competitive antagonism with para-aminobenzoic acid (PABA). Microorganisms that require exogenous folic acid and do not synthesize folic acid (pteroylglutamic acid) are not susceptible to the action of sulfonamides. Resistant strains are capable of using folic acid precursors or preformed folic acid.

Sulfonamide antimicrobials exist as 3 forms in serum: free, conjugated (ie, acetylated and possibly others), and protein bound. The free form is considered therapeutically active.

Sulfadiazine

Through competitive antagonism of PABA, sulfadiazine interferes with microbial growth. It is useful in the treatment of toxoplasmosis.

Trimethoprim and sulfamethoxazole (Bactrim DS, Septra DS)

Trimethoprim/sulfamethoxazole exerts bacteriostatic action through competitive antagonism with PABA. The double-strength tablet contains 800 mg of sulfamethoxazole and 160 mg of trimethoprim. The regular strength tablet contains 400 mg of sulfamethoxazole and 80 mg of trimethoprim.


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