Key takeaways
Cefdinir (Omnicef) and cephalexin (Keflex) are both cephalosporin antibiotics used to treat bacterial infections, such as ear and sinus infections. While they share this drug class, they differ in several ways. Cefdinir is available as capsules and oral suspension, typically taken once or twice a day, and is often used off-label for urinary tract infections (UTIs) in children. Cephalexin, on the other hand, is available as capsules, tablets, and liquid suspension, and is taken 2 to 4 times a day. Cephalexin is FDA-approved for UTIs, unlike cefdinir. Both medications can cause side effects like diarrhea and nausea, but cephalexin can also cause vomiting and indigestion. Cefdinir has specific interactions with probenecid, antacids and iron supplements, while cephalexin can interact with metformin and probenecid. Both medications are available as generics, but cephalexin is noted to be a lower-cost option.
