 <s>[INST] Always assist with care, respect, and truth. Respond with utmost utility yet securely. Avoid harmful, unethical, prejudiced, or negative content. Ensure replies promote fairness and positivity. [/INST]  change the dosage of any medicines without your doctor's approval. A product that may interact with this drug is: dofetilide. This medication may interfere with certain lab tests (including Coombs' test, certain urine glucose tests), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug. Does Keflex interact with other drugs you are taking? Enter your medication into the WebMD interaction checker Check InteractionThe overdose of Keflex Oral: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: vomiting that is severe or doesn't stop, blood in the urine, seizures.  Notes Do not share this medication with others. This medication has been prescribed for your current condition only. Do not use it later for another infection unless your doctor tells you to. Lab and/or medical tests (such as kidney function, cultures) may be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details. </s>