NOTE: With ALL antibiotics there are many factors to take into consideration. These examples below are JUST examples, and you should always follow your physicians instructions when taking antibiotics.
Penicillin is generally well-tolerated in people with kidney disease, so it may be a good alternative to cephalexin for these individuals.
Compared to cephalexin, bactrim (trimethoprim / sulfamethoxazole) may be more useful in the treatment and prevention of opportunistic infections in HIV/AIDs patients, patients undergoing organ transplants, or other infections.
Cipro (ciprofloxacin) may be more effective than cephalexin as a post-exposure treatment following an accidental anthrax inhalation or other infections. It’s also quite cheap, comparatively.
Cephalexin Alternative for Dogs: Tetracycline
Prescription tetracycline is safe for dogs. It may be a good alternative if cephalexin and other antibiotics fail to treat the underlying bacterial infection.
NOTE: Do not attempt to give pets any medications other than the ones prescribed by a veterinarian.
Cephalexin Alternative for Penicillin Allergy
People with penicillin allergy may be more likely to also be allergic to cephalexin. For these individuals, alternative antibiotic medications may include clarithromycin, doxycycline (Doxy-100, Monodox, Oracea), and erythromycin (E.E.S. 400, E.E.S. Granules, EryPed 200).
NOTE: just because you are allergic to penicillins does not necessarily mean you will be allergic to cephalexin (but there may be increased chance due to similar chemical structure)