No. Keflex is a cephalosporin antibiotic which is chemically related to a penicillin. It does not contain a sulfa group in its structure, so it is not a sulfa drug.
Iron products, antacids and milk should not be taken at the same time as a dose of tetracycline. You can take the medication an hour before you ingest vitamins containing iron, antacids or milk or...
The short answer is no. According to Wikipedia, this is part of the tetracycline class of antibiotics. They are not chemically related to Penicillins or Sulfates. However, one should always consult...