Sulfaphenazole

(It is in experimental stages.)

It is a long acting sulfonamide antibacterial.

Action:
It specifically inhibits CYP2C9 i.e an important cytochrome P450 enzyme important in the oxidation of endogenous compounds.

Sulfametopyrazine

(It is now withdrawn)
It is a long acting sulfonamide.

Action:
It competitively inhibits the bacterial enzyme dihydropteroate synthetase.

Uses:
It is used for Urinary tract infections, Respiratory tract infections and malaria.

Sulfamethoxy-pyridazine

It is a long acting sulfonamide.

Uses:
It is used to treat Urinary Tract Infections, Pneumonia and bronchitis.

Sulfadoxine

Sulfadoxine is an intermediate to long acting sulfonamide.

Uses:
It is generally used in combination with other drugs

Sulfacetamide

It is an intermediate acting sulfonamide and is available in the salt form alongwith sodium.

Mechanism of Action:
It competitively inhibits the bacterial enzyme para-aminobenzoic acid resulting in the inhibition of the synthesis of the folic acid.

Uses:
It is used in the treatment of skin infections and orally it is useful in the treatment of Urinary tract infections.

Sulfisomidine

It is also known as sulfasomidine and it is a short acting sulfonamide.

It is similar to sulfadimidine.

Sulfisoxazole

It is a short acting sulfonamide.

Mechanism of Action:
It inhibits the folic acid production of bacteria by competitive inhibition of the enzyme dihydropteroate synthetase.

Uses:
It is used for the treatment of Urinary Tract Infections, Acute otitis media, meningococcal meningitis, malaria and other bacterial infections.