Key takeaways
Metronidazole (Flagyl) and cephalexin are both antibiotics, but they belong to different classes and treat different types of infections. Metronidazole is a nitroimidazole antibiotic that treats bacterial and parasitic infections, such as trichomoniasis and bacterial vaginosis. It is taken three times a day and should not be mixed with alcohol due to serious side effects. Cephalexin, on the other hand, is a cephalosporin antibiotic used to treat bacterial infections like UTIs, ear infections, and respiratory infections. It is typically taken 2 to 4 times a day and does not have a direct interaction with alcohol. Metronidazole can cause a metallic taste and in rare cases serious brain and nerve problems, while cephalexin can lead to allergic reactions and C. difficile-related diarrhea. Both medications are available as lower-cost generics and require a prescription.
