Heartburn can be confused with early symptoms of heart attack. Seek emergency medical attention if you have chest pain or heavy feeling, dizziness, pain spreading to the arm or shoulder, sweating, nausea or vomiting, and a general ill feeling.
You should not use this medication if you have trouble swallowing, vomiting with blood, bloody or tarry stools, or if you are allergic to famotidine or similar medications such as ranitidine (Zantac), cimetidine (Tagamet), or nizatidine (Axid).
Ask a doctor or pharmacist about using famotidine, calcium, and magnesium if you have nausea, vomiting, stomach pain, unusual weight loss, wheezing or trouble breathing when you have heartburn, or if you have had heartburn for longer than 3 months.
Do not use more than two tablets in 24 hours.
Stop using famotidine, calcium, and magnesium if stomach pain continues or if you need to take this product for more than 14 days. You may have a more serious stomach condition that requires different treatment.