**Sulfamethoxazole** is an antibiotic that is usually combined with **trimethoprim** to form **co-trimoxazole** (brand names include Bactrim and Septra). This combination is more effective because the two drugs work synergistically to block bacterial folate synthesis.
# **Uses of Sulfamethoxazole (with Trimethoprim):**
1. **Urinary Tract Infections (UTIs)** – Commonly used to treat bacterial UTIs.
2. **Respiratory Infections** – Such as bronchitis, otitis media (middle ear infections), and sinusitis.
3. **Traveler’s Diarrhea** – Caused by susceptible bacteria like *E. coli*.
4. **Pneumocystis jirovecii Pneumonia (PCP