Famotidine is a common over-the-counter (OTC) and prescription medication that reduces stomach acid. As a histamine-2 (H2) blocker, it alleviates symptoms of excess stomach acid, such as heartburn, acid indigestion, and sour stomach.
Typical OTC Dosing
OTC famotidine is available in 10 mg and 20 mg strengths. For occasional heartburn, adults can take one 10 mg or 20 mg tablet when symptoms begin. To prevent symptoms, take 10 mg or 20 mg 10 to 60 minutes before consuming food or beverages that trigger heartburn. Adults should not exceed two doses or 40 mg within a 24-hour period. OTC famotidine is for short-term use, typically up to 14 days. Consult a healthcare professional if symptoms persist beyond this period.
Prescription Use and Dosing
Famotidine is also prescribed in higher doses for persistent or severe conditions. Prescription strengths include 20 mg and 40 mg tablets. These higher doses manage chronic conditions like gastroesophageal reflux disease (GERD), stomach ulcers, duodenal ulcers, and conditions with excessive stomach acid production, such as Zollinger-Ellison syndrome.
For GERD, a healthcare provider may prescribe 20 mg twice daily for up to six weeks, or 20 to 40 mg twice daily for up to 12 weeks for erosive esophagitis. Duodenal ulcers are typically treated with 40 mg once daily at bedtime or 20 mg twice daily for up to eight weeks, with a 20 mg maintenance dose once daily at bedtime to prevent recurrence. Stomach ulcers are often treated with 40 mg at bedtime for up to eight weeks. Higher doses, up to 640 mg daily in divided doses, may be used for pathological hypersecretory conditions, often starting at 20 mg every six hours. Dosages and treatment durations are determined and monitored by a healthcare professional based on individual needs and condition severity.
Important Safety Information
While generally well-tolerated, famotidine can cause side effects. Common side effects include headaches, dizziness, constipation, or diarrhea. More serious, less frequent effects include confusion, hallucinations, agitation, seizures, rapid heartbeats, sudden dizziness, unexplained muscle pain, or liver changes. Severe allergic reactions (hives, difficulty breathing, or swelling of the face, lips, tongue, or throat) require immediate medical attention.
Famotidine can interact with other medications by altering their absorption. For instance, it may affect certain antifungal medications (e.g., ketoconazole, itraconazole), some HIV medications, and tizanidine. Discuss all medications, including OTC drugs, vitamins, and supplements, with a pharmacist or doctor to avoid potential interactions. Individuals with kidney problems may require dosage adjustments, as kidneys primarily clear famotidine. Although generally considered safe during pregnancy and breastfeeding, pregnant or breastfeeding individuals should consult their healthcare provider before use.
When to Seek Medical Advice
While famotidine offers effective relief for acid-related symptoms, certain signs indicate the need for medical evaluation. Consult a doctor if heartburn or indigestion symptoms persist for more than two weeks despite OTC famotidine, or if symptoms worsen. Persistent symptoms could signal an underlying condition requiring professional diagnosis and treatment. Seek immediate medical attention for severe symptoms like difficulty or painful swallowing, or the sensation of food getting stuck in your throat. Other concerning indicators include vomiting blood, black or tarry stools, unexplained weight loss, or severe chest pain spreading to the arm, neck, or jaw (which could indicate a heart attack). Seek prompt medical help if an overdose is suspected or severe adverse reactions occur.