Sulfamethoxazole
Sulfamethoxazole works by stopping the growth of bacteria. It inhibits the production of folic acid, a vitamin bacteria need to grow and multiply. When combined with trimethoprim, it becomes more effective and helps prevent bacterial resistance.
- Description
- Additional Information
- Uses
- Interactions
- Side Effects
Sulfamethoxazole is a sulfonamide antibiotic that works by stopping the growth of bacteria. It’s most commonly used in combination with trimethoprim (as co-trimoxazole or TMP-SMX) to increase its effectiveness. This combination is often prescribed under brand names such as Bactrim, Septra, or Sulfatrim.
Sulfamethoxazole interferes with the production of folic acid, a vital nutrient bacteria need to grow and multiply, thereby helping to eliminate bacterial infections from the body.
- Drug Class: Sulfonamide antibiotic
- Chemical Formula: C10H11N3O3S
- Available Forms: Tablets, oral suspension, and intravenous (IV) formulations (usually combined with trimethoprim)
- Prescription Required: Yes
- Storage: Store at room temperature, away from light and moisture
Sulfamethoxazole (typically with trimethoprim) is used to treat a variety of bacterial infections, including:
- Urinary Tract Infections (UTIs)
- Bronchitis
- Traveler’s diarrhea
- Middle ear infections (otitis media)
- Pneumocystis jirovecii pneumonia (PCP) in immunocompromised patients (e.g., HIV/AIDS)
- Shigellosis (intestinal infection)
- Certain types of skin or soft tissue infections
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Sulfamethoxazole can interact with several medications. Key interactions include:
- Warfarin – may increase bleeding risk.
- Phenytoin – may increase toxicity.
- Methotrexate – may enhance side effects and toxicity.
- Cyclosporine – may cause kidney damage.
- Oral hypoglycemics (like glipizide, glyburide) – may increase risk of low blood sugar.
- Diuretics (especially thiazides) – may increase risk of allergic reactions or blood disorders.
Always inform your doctor of all medications and supplements you’re taking before starting this drug.
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Common and serious side effects can occur.
Common Side Effects:
- Nausea, vomiting
- Loss of appetite
- Mild rash or itching
- Diarrhea
Serious Side Effects (Seek medical attention immediately):
- Severe allergic reactions (rash, hives, swelling, difficulty breathing)
- Liver problems (yellowing of skin/eyes, dark urine)
- Blood disorders (unusual bleeding, tiredness, or pallor)
- Kidney issues (changes in urine output, blood in urine)
- High potassium levels (muscle weakness, irregular heartbeat)