DESCRIPTION
An anti-infective agent that is used topically to treat skin infections and orally for urinary tract infections. [PubChem]
CHEMICAL FORMULA
C8H10N2O3S
COMPOSITION
Sulphacetamide Sodium IP 20% w/v HPMC IP 0.25% w/v Phenylethyl Alcohol USP 0.5% v/v
INDICATION
For the treatment of bacterial vaginitis, keratitis, acute conjunctivitis, and blepharitis.
PHARMACODYNAMICS
Sulfacetamide 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.
MECHANISM
Sulfacetamide is a competitive inhibitor of bacterial para-aminobenzoic acid (PABA), an essential component for bacterial growth (according to the Woods-Fildes theory). The inhibited reaction is necessary in these organisms for the synthesis of folic acid.
HALF LIFE
7-12.8 hours
TOXICITY
Oral LD50 Mouse : 16500 mg/kg. Side effects include moderate to severe erythema (redness) and moderate edema (raised kin), nausea, vomiting, headache, dizziness, and tiredness. Higher exposure causes unconsciousness.