Allergy alert: Do not use if you are allergic to famotidine or other acid reducers. Do not use if you have trouble or pain swallowing food, vomiting with blood, or bloody or black stools. These may be signs of a serious condition. See your doctor, with other acid reducers.. Ask a doctor before use if you have had heartburn over 3 months. This may be a sign of a more serious condition., heartburn with lightheadedness, sweating, or dizziness, chest pain or shoulder pain with shortness of breath; sweating; pain spreading to arms, neck or shoulders; or lightheadedness, frequent chest pain, frequent wheezing, particularly with heartburn, unexplained weight loss, nausea or vomiting, stomach pain.. Ask a doctor or pharmacist before use if you are presently taking a prescription drug. Antacids may interact with certain prescription drugs. Stop use and ask a doctor if your heartburn continues or worsens, you need to take this product, for more than 14 days.. If pregnant or breast-feeding, ask a health professional before use. Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center right away (1-800-222-1222). Do not use if printed foil under cap is broken or missing.