Key takeaways
Sulfamethoxazole/trimethoprim (Bactrim) and penicillin v potassium (Penicillin VK) are antibiotics used to treat bacterial infections but differ in their classes and applications. Bactrim, a sulfonamide antibiotic combining sulfamethoxazole and trimethoprim, is effective for urinary tract infections, ear infections, and traveler's diarrhea. It is available in tablet, liquid, and injection forms but is not suitable for those with a sulfa allergy or pregnant women. Common side effects include nausea, vomiting, and diarrhea. Penicillin VK, a penicillin antibiotic, is primarily used for strep infections and some pneumococcal and staph infections. It is available as a generic in tablet and suspension forms and has fewer side effects, such as nausea and diarrhea. However, many bacteria are resistant to it, and it is not recommended for those allergic to penicillin or cephalosporins. Both medications require completing the full course to prevent bacterial resistance.
