Rantac Mint Syrup contains Ranitidine, which has been withdrawn or restricted in many countries due to safety concerns related to impurities. For a 75-year-old patient with diabetes, it should not be used without a doctor’s advice, especially if there are kidney or other health issues. Safer and more commonly used alternatives, such as famotidine or proton pump inhibitors, may be preferred depending on his condition. It is best to consult his physician before starting or continuing this medicine to ensure safe and appropriate treatment.