Famotidine (Pepcid): Uses, Dosage, Side Effects, and Safe Tips

If you’re dealing with heartburn, acid reflux (GERD), or stomach ulcers, famotidine—often known by the brand name Pepcid—is a well-studied medicine that can help. This easy-to-read guide explains what famotidine is, how it works, who it’s for, how to take it correctly, side effects to watch for, and answers to common questions. The goal is to help you make informed, safe choices and to give searchers a clear, trustworthy resource.

Educational disclaimer: This article is for general information only and isn’t medical advice. Always follow your healthcare professional’s guidance and the label for your specific product. Do not use famotidine longer than 14 days in a row without medical supervision.

What is Famotidine?

Famotidine is an H2 blocker (histamine-2 receptor antagonist). It reduces the amount of acid your stomach makes, which helps relieve heartburn, acid indigestion, and sour stomach. Prescription famotidine is also used for gastroesophageal reflux disease (GERD), erosive esophagitis, and stomach or duodenal ulcers. In hospitals, an injectable form may be used when people cannot take medicine by mouth.

Available formulations

• Tablets: 10 mg, 20 mg (OTC); 20 mg, 40 mg (Rx)
• Oral suspension (liquid): usually 40 mg/5 mL (prescription)
• Chewable/combination products: e.g., famotidine with antacids (calcium carbonate + magnesium hydroxide) for rapid symptom relief
• Injection (hospital use): for IV or IM administration when needed

How Does Famotidine Work?

Stomach acid is stimulated by histamine acting on H2 receptors in acid-producing cells. Famotidine blocks H2 receptors, which:

• Lowers stomach acid production (both daytime and nighttime)
• Reduces irritation of the esophagus and stomach lining
• Eases heartburn symptoms and supports healing of ulcers and esophagitis

Onset & duration

• Starts working in 30–60 minutes
• Symptom relief can last 10–12 hours (sometimes longer with prescription doses)

Common Uses

• Frequent heartburn (two or more days per week)*
• GERD (acid reflux causing burning, regurgitation, or chronic cough)
• Erosive esophagitis (inflammation/erosion of the esophagus)
• Stomach (gastric) or duodenal ulcers
• Zollinger-Ellison syndrome (rare condition with very high acid output; specialist care)

*OTC famotidine treats symptoms of heartburn. If symptoms occur more than 14 days in a row or keep coming back after treatment, see a clinician.

Dosage & Administration

Always read your specific product label. Doses below are typical ranges—your clinician may adjust them based on your condition, kidney function, age, and other medicines.

Over-the-Counter (Adults & Age ≥12)

• Heartburn/acid indigestion:
  • 10–20 mg by mouth once or twice daily.
  • Take 15–60 minutes before food or drinks that trigger heartburn, or when symptoms start.
  • Do not exceed 2 tablets in 24 hours unless directed by a clinician.
  • Limit self-treatment to 14 days. If symptoms persist, seek medical advice.

Prescription (Adults)

• GERD (symptomatic): 20 mg twice daily for up to 6 weeks
• Erosive esophagitis: 20–40 mg twice daily for up to 12 weeks
• Duodenal ulcer (active): 40 mg at bedtime for 4–8 weeks
• Maintenance (duodenal ulcer): 20 mg at bedtime
• Gastric ulcer (active): 40 mg at bedtime for up to 8 weeks
• Zollinger-Ellison: starting 20 mg every 6 hours; specialists may increase as needed

Children

• Famotidine can be prescribed for children; dosing is usually based on weight (mg/kg). Because correct pediatric dosing requires professional calculation and monitoring, only use famotidine in children under direct medical guidance. OTC products are not for children under 12 unless a clinician advises otherwise.

Kidney (Renal) Dose Adjustments

Famotidine is cleared by the kidneys. If you have kidney problems (e.g., creatinine clearance <50 mL/min) or are on dialysis, your clinician may lower the dose or extend the dosing interval to reduce the risk of side effects (see “Warnings & precautions”).

How to Take Famotidine: Step-by-Step

1. Identify triggers. Greasy, spicy, or acidic foods; coffee; alcohol; and large late-night meals can worsen reflux.
2. Take with water. Swallow tablets with a full glass of water. For chewables or combo chewables, chew completely before swallowing.
3. Timing matters. For prevention, take 15–60 minutes before a trigger meal.
4. Lifestyle helps. Eat smaller meals, avoid lying down within 3 hours after eating, elevate the head of the bed, and maintain a healthy weight.
5. Track symptoms. If you need OTC famotidine more than 2–3 days per week for several weeks, talk to a clinician to rule out other conditions.

Side Effects

Common (usually mild):

• Headache
• Dizziness or drowsiness
• Constipation or diarrhea
• Nausea, abdominal discomfort

Less common but important:

• Confusion, agitation, or hallucinations (more likely in older adults or those with kidney impairment—seek medical care)
• Allergic reactions (rash, itching, swelling of face/lips/tongue, trouble breathing—emergency care)
• Irregular heartbeat or palpitations (rare; seek care)
• Vitamin B12 deficiency with very long-term use (rare; discuss if you take acid-reducing medicines for months/years)

Stop the medicine and seek help if you develop chest pain, vomiting blood, black stools, unexplained weight loss, or trouble swallowing.

Warnings & Precautions

• Alarm symptoms: Persistent or severe heartburn, chest pain, pain radiating to arm/jaw, unexplained weight loss, frequent vomiting, blood in vomit/stool, or symptoms lasting beyond 14 days need medical evaluation.
• Kidney disease: Use lower doses or longer intervals as directed by a clinician.
• Liver disease: Usually well tolerated, but discuss dosing with your clinician.
• Older adults: Greater sensitivity to confusion or dizziness—use with caution.
• Pregnancy & breastfeeding: Generally considered compatible. Still, discuss with your clinician before starting any medication.
• Not for certain conditions: Do not use famotidine to treat COVID-19 or infections; it is not an antiviral.
• Phenylketonuria (PKU): Some chewable or ODT products may contain phenylalanine—check labels.

Drug & Food Interactions

Famotidine has few interactions, but stomach acidity matters for how some drugs are absorbed.

Avoid or use caution with (talk to your clinician):

• Drugs needing stomach acid to absorb well: e.g., atazanavir, rilpivirine, dasatinib, erlotinib, certain azole antifungals (ketoconazole, itraconazole), cefditoren, and iron salts.
• QT-prolonging medicines in patients with kidney impairment (risk may rise if famotidine accumulates).
• Alcohol, caffeine, and very spicy or acidic foods can worsen reflux—limit if they trigger your symptoms.
• Antacids: You can use calcium/magnesium antacids for quick relief; separate some medications as directed to avoid absorption issues.

Always give your pharmacist or clinician a complete medication list, including supplements and herbs.

Famotidine vs. Other Treatments

H2 blockers vs. Proton Pump Inhibitors (PPIs):

• Relief speed: Famotidine often works faster than a PPI on the first dose (30–60 minutes vs. several hours).
• Strength & healing: PPIs (e.g., omeprazole) generally reduce acid more strongly and are preferred for moderate-to-severe GERD or to heal erosive esophagitis.
• Nighttime symptoms: Famotidine can be helpful, especially for nocturnal acid breakthrough or as as-needed therapy.
• Tolerance: With daily long-term H2 blocker use, the body may develop tolerance (reduced effect). PPIs don’t show the same quick tolerance but have their own risks when used long term.
• Antacids: Work immediately but briefly; best for on-the-spot relief. Combination chewables (famotidine + antacids) can give fast and sustained relief.

Cost & OTC Status

• OTC availability: Widely available as famotidine 10 mg and 20 mg tablets and in chewable combo products.
• Prescription: 20 mg and 40 mg tablets and oral suspension are available in generic.
• Cost: Generics are typically low cost. Prices vary by brand, pharmacy, and insurance.

Special: Picking the Right Formulation

• Occasional heartburn before trigger meals: 10–20 mg tablet taken 15–60 minutes before eating.
• Frequent symptoms or night-time burning: Ask your clinician about 20 mg twice daily (Rx) or short 14-day OTC courses with lifestyle changes.
• Trouble swallowing tablets or need precise dosing: Oral suspension (prescription) can help.
• Want quick + longer relief: Consider chewable combination products (famotidine with antacids).
• Hospital or cannot take by mouth: Injection (clinician-directed).

Proper Care & Use

• Storage: Keep at room temperature, away from excess heat and moisture.
• Adherence: Take at the same times each day if prescribed regularly.
• Diet & habits:
  • Eat smaller meals; avoid lying down for 3 hours after eating.
  • Limit alcohol, coffee, chocolate, peppermint, tomato, and spicy or fatty foods if they trigger symptoms.
  • Elevate the head of your bed by 6–8 inches for nighttime reflux.
  • Stop smoking; it reduces lower-esophageal-sphincter tone.
• When to get help: If you need OTC famotidine for more than 14 days, or symptoms return quickly after stopping, see a clinician.

FAQ (12 Quick Answers)

1. What does famotidine treat?
   Heartburn, acid indigestion, GERD, erosive esophagitis, and stomach/duodenal ulcers (under medical care).
2. Is famotidine the same as Pepcid?
   Yes. Pepcid is a brand name for famotidine.
3. How fast does it work?
   Usually within 30–60 minutes, with relief lasting up to 10–12 hours.
4. Can I take famotidine every day?
   OTC use is for up to 14 days. For long-term daily use, talk to a clinician to check the cause of your symptoms and the best plan.
5. Is 20 mg stronger than 10 mg?
   Yes—20 mg provides longer and stronger acid reduction than 10 mg. Use the lowest effective dose.
6. Can I combine famotidine with antacids?
   Yes. Antacids give quick relief; famotidine maintains control. Combination chewables are designed for this.
7. Is famotidine safe in pregnancy or while breastfeeding?
   Generally considered compatible, but always ask your clinician before starting any medicine.
8. Does famotidine cause drowsiness?
   It can cause drowsiness or dizziness in some people. Avoid driving or risky tasks until you know how you react.
9. What if I have kidney disease?
   You may need a lower dose or less frequent dosing. Talk to your clinician before using.
10. Can famotidine treat COVID-19 or infections?
    No. Famotidine is not an antiviral and should not be used for COVID-19 treatment or prevention.
11. What if I miss a dose?
    Take it when you remember unless it’s near the time for the next dose. Don’t double up.
12. When should I see a doctor?
    If you have trouble swallowing, vomiting, blood in stool/vomit, chest pain, unexplained weight loss, or if heartburn persists >14 days despite OTC use.

Final Thoughts (Best-Practice Summary)

• Start smart: For occasional heartburn, 10–20 mg before a trigger meal may help.
• Limit self-treatment: No more than 14 days in a row without medical advice.
• Check interactions: Especially medicines that require stomach acid for absorption.
• Adjust for kidneys: Ask about dosing if you have kidney impairment.
• Consider alternatives: If symptoms are frequent or severe, PPIs or other therapies may be more effective—ask your clinician.
• Lifestyle first: Pair famotidine with diet and habit changes for the best results.