In some of these reactions, supportive therapy may be necessary. Who Makes Keflex? Keflex is manufactured jos ostaa keflex by Advancis Pharmaceuticals. Nasdaq: MBRK News is pharmaceutical company focused on developing and commercializing anti-infective products that fulfill unmet medical needs. Do not use any medicine to stop the diarrhea unless your doctor has told you to. If you do not have dose-measuring device, ask your pharmacist for one. Altered Laboratory Tests Prolonged prothrombin time, increased BUN, increased creatinine, elevated alkaline phosphatase, elevated bilirubin, elevated LDH, pancytopenia, leukopenia, and agranulocytosis. You may take this medicine with food if stomach upset occurs.