PRECAUTIONS: Before using famotidine, tell your doctor or pharmacist if you are allergic to it; or to other acid reducers (e.g., cimetidine, ranitidine); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: immune system problems, kidney problems, liver problems, lung problems (e.g., asthma, chronic obstructive pulmonary disease-COPD), other stomach problems (e.g., tumors).Some symptoms may actually be signs of a more serious condition. Tell your doctor immediately if you have: heartburn combined with lightheadedness/sweating/dizziness, chest pain or shoulder/jaw pain (especially with trouble breathing), pain spreading to arms/neck/shoulders, unexplained weight loss.This drug may make you dizzy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Limit alcoholic beverages.Kidney function declines as you grow older. This medication is removed by the kidneys. Therefore, elderly people may be at greater risk for side effects while using this drug. Caution is advised when using this drug in the elderly because they may be more sensitive to its effects, especially confusion and dizziness.Famotidine should be used only when clearly needed during pregnancy. Discuss the risks and benefits with your doctor.This drug passes into breast milk. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Some products that may interact with this drug include: atazanavir, azole antifungals (e.g., itraconazole, ketoconazole), dasatinib.Check the labels on all your medicines because they may contain aspirin or aspirin-like NSAIDs (e.g., ibuprofen, naproxen) that can cause stomach irritation/ulcers. Ask your doctor or pharmacist about the safe use of these products. Low-dose aspirin, as prescribed by your doctor for specific medical reasons such as heart attack or stroke prevention (usually at dosages of 81-325 milligrams per day), should be continued. Consult your doctor for more details.This medication and other H2 blockers (e.g., cimetidine, ranitidine, nizatidine) are available both over-the-counter and by prescription. Do not take them at the same time.

Report Problems to the Food and Drug Administration You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088. Need help identifying pills and medications? Use the pill identifier tool on RxList.