2. Sulphonamides
• A widely used class of agents for treatment of
urinary tract infections.
• The most frequently used sulphonamide,
sulfamethoxazoleis routinely combined with
trimethoprim for synergistic activity against
gram-negative and limited gram-positive
pathogens.
• Sulfamethoxazole is combined with the
trimethoprim to target two different steps in
folate metabolism of the bacterial cell.
3. Sulfamethoxazole-trimethoprim
• The efficacy of sulfamethoxazole and
trimethoprim over the use of single agent has
rendered this combination far and away the
most frequently used of the salphonamides.
• Indications include urinary tract infection,
otitis media, chronic bronchitis, pneumocystis
carinii pneumonia, typhoid, shigellosis.
• It is adminstered orally, but an IV formulation
is available for use.
4. Sulfamethoxazole-trimethoprim
• It is fairly well absorbed orally and each agent has
a half-life of approximately 10 to 11 hours.
• The drugs are primarily cleared renally.
• The adult dose and duration vary based on
indication.
• A typical dose for treating urinary tract infections
in adults is one double-strength tablet
(sulfamethoxazole 800mg/trimethoprim 160mg)
twice daily for 10 to 14 days.
5. Sulfamethoxazole-trimethoprim
• Adverse effects include anorexia, nausea,
vomiting and rash.
• Occasional rare reactions include
hepatotoxicity, confusion and seizures.
• Stevens-Johnson syndrome, toxic epidermal
necrolysis, and exfoliative dermatitis are all
possible.
