Famotidine is used to treat ulcers of the stomach and intestines and to prevent intestinal ulcers from coming back after they have healed. This medication is also used to treat certain stomach and throat (esophagus) problems (such as erosive esophagitis, gastroesophageal reflux disease-GERD, Zollinger-Ellison syndrome). It works by decreasing the amount of acid your stomach makes. It relieves symptoms such as cough that doesn't go away, stomach pain, heartburn, and difficulty swallowing. Famotidine belongs to a class of drugs known as H2 blockers.

This medication is also available without a prescription. It is used to prevent and treat heartburn and other symptoms caused by too much acid in the stomach (acid indigestion). If you are taking this medication for self-treatment, it is important to read the manufacturer's package instructions carefully so you know when to consult your doctor or pharmacist.

Take this medication by mouth with or without food as directed by your doctor, usually once or twice daily. If you are taking this medication once daily, it is usually taken right before bedtime.

The dosage and length of treatment are based on your medical condition and response to treatment. Children's dosage may also be based on weight. You may take other medications (such as antacids) for your condition as recommended by your doctor. Follow your doctor's instructions carefully. Consult your doctor or pharmacist if you have any questions.

Take this medication regularly in order to get the most benefit from it. To help you remember, take it at the same time(s) each day. Do not increase your dose or take it more often than prescribed. Do not stop taking this medication without your doctor's approval because this may delay healing of the ulcer.

If you are using nonprescription famotidine for self-treatment of acid indigestion or heartburn, take 1 tablet by mouth with a glass of water as needed. To prevent heartburn, take 1 tablet by mouth with a glass of water 15-60 minutes before eating food or drinking beverages that cause heartburn. Do not use more than 2 tablets in 24 hours unless directed by your doctor. Do not take for more than 14 days in a row without talking with your doctor.

Tell your doctor if your condition does not get better or if it gets worse.

Headache, constipation, or diarrhea may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

If your doctor has directed you to use this medication, remember that your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including:

• easy bruising/bleeding
• signs of infection (such as sore throat that doesn't go away, fever, chills)
• mental/mood changes (such as restlessness, confusion, depression, hallucinations)

Get medical help right away if you have any very serious side effects, including:

• fast/slow/irregular heartbeat
• severe dizziness
• fainting
• seizure

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before taking famotidine, tell your doctor or pharmacist if you are allergic to it; or to other H2 blockers (such as 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 (such as asthma, chronic obstructive pulmonary disease-COPD)
• other stomach problems (such as tumors)

Some symptoms may actually be signs of a more serious condition. Get medical help right away if you have:

• heartburn with lightheadedness/sweating/dizziness
• chest/jaw/arm/shoulder pain (especially with shortness of breath, unusual sweating)
• unexplained weight loss

In addition, before you self-treat with this medication, get medical help right away if you have any of these signs of a serious condition:

• trouble/pain swallowing food
• bloody vomit
• vomit that looks like coffee grounds
• bloody/black stools
• heartburn for over 3 months
• frequent chest pain
• frequent wheezing (especially with heartburn)
• nausea/vomiting
• stomach pain

Do not use to treat children younger than 12 unless directed by the doctor.

Older adults may be more sensitive to the side effects of this drug, especially mental/mood changes (such as confusion), seizure, or unusual tiredness.

During pregnancy, famotidine should be used only when clearly needed. Discuss the risks and benefits with your doctor.

This drug passes into breast milk. Consult your doctor before breastfeeding.

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.

A product that may interact with this drug is:

• fezolinetant

Some products need stomach acid so that the body can absorb them properly. Famotidine decreases stomach acid, so it may change how well these products work. Some affected products include atazanavir, dasatinib, certain azole antifungals (such as itraconazole, ketoconazole), levoketoconazole, pazopanib, sparsentan, among others.

Do not take this medication with other products that contain famotidine or other H2 blockers (cimetidine, nizatidine, ranitidine).

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 1-800-222-1222. Canada residents can call 1-844-764-7669.

Do not share this medication with others.

Lifestyle changes such as stress reduction programs, stopping smoking, limiting alcohol, and diet changes (such as avoiding caffeine and certain spices) may help this medication work better. Talk to your doctor or pharmacist about lifestyle changes that might benefit you.

Lab and/or medical tests (such as endoscopy, kidney function) may be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.