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Kelfizina: Full Drug Profile

Medically reviewed by Min Clinic Staff | Updated: January 2026

Kelfizina - General Information

Long-acting plasma-bound sulfonamide used for respiratory and urinary tract infections and also for malaria. [PubChem]

 

Pharmacology of Kelfizina

Kelfizina is a sulfonamide antibiotic. The sulfonamides are synthetic bacteriostatic antibiotics with a wide spectrum against most gram-positive and many gram-negative organisms. However, many strains of an individual species may be resistant. Sulfonamides inhibit multiplication of bacteria by acting as competitive inhibitors of p-aminobenzoic acid in the folic acid metabolism cycle. Bacterial sensitivity is the same for the various sulfonamides, and resistance to one sulfonamide indicates resistance to all. Most sulfonamides are readily absorbed orally. However, parenteral administration is difficult, since the soluble sulfonamide salts are highly alkaline and irritating to the tissues. The sulfonamides are widely distributed throughout all tissues. High levels are achieved in pleural, peritoneal, synovial, and ocular fluids. Although these drugs are no longer used to treat meningitis, CSF levels are high in meningeal infections. Their antibacterial action is inhibited by pus.

 

Kelfizina for patients

Patient Information:

Discuss with your doctor about the risks of taking Sulfametopyrazine. Make sure you let the doctor know
if you are pregnant, breast feeding, or you have liver, renal problems or any other medical conditions.

 

Kelfizina Interactions

Drug Interactions:

Sulfametopyrazine increases the effects of the some drugs, including:
ACETOHEXAMIDE
CHLORPROPAMIDE
CLOZAPINE
GLIBENCLAMIDE
GLIBORNURIDE
GLICLAZIDE
GLIMEPIRIDE
GLIPIZIDE
GLIQUIDONE
GLYMIDINE
TOLAZAMIDE
TOLBUTAMIDE

Sulfametopyrazine decreases the effects of the follwing drugs:
ETHINYLESTRADIOL
ORAL CONTRACEPTIVES
POTASSIUM AMINOBENZOATE

 

Kelfizina Contraindications

Sulfametopyrazine is contraindicated in patients who are allergic to Sulfonamide, or have adverse
reactions to cotrimoxazole or sulphonamides. It is also contraindicated in the following medical
conditions:
Disorders of porphyrin metabolism
Glucose-6-phosphate dehydrogenase deficiency anaemia
Sulphonamide poisoning

 

Additional information about Kelfizina

Kelfizina Indication

For the treatment of urinary tract infection and chronic bronchitis.

Mechanism Of Action
Kelfizina is a competitive inhibitor of bacterial para-aminobenzoic acid (PABA), a substrate of the enzyme dihydropteroate synthetase. The inhibited reaction is necessary in these organisms for the synthesis of folic acid.
Generic Name
Sulfametopyrazine
Drug Category
Antimalarials; Anti-Infectives; Anti-Infective Agents, Urinary
Drug Type
Small Molecule; Approved; Withdrawn
Other Brand Names containing Sulfametopyrazine
Dalysep; Farmitalia 204/122; Kelfizin; Kelfizina; Kelfizine; Kelfizine W; Longum; Polycidal; SMP; SMP2; Solfametopirazina [Dcit]; Sulfalen; Sulfalene; Sulfalene [Usan-Inn]; Sulfaleno [Inn-Spanish]; Sulfalenum [Inn-Latin]; Sulfamethopyrazine; Sulfamethoxypyrazine; Sulfamethoxysuccinate; Sulfametoxypyridazin; Sulfapyrazinemethoxine; Sulfapyrazinemethoxyine; Sulfapyrazinemethoxyne;
Chemical IUPAC Name
4-amino-N-(3-methoxypyrazin-2-yl)benzenesulfonamide
Chemical Formula
C11H12N4O3S
Organisms Affected
Gram negative, positive bacteria and plasmodium