how long does it take for famotidine to work for acid reflux

January 4, 2026

Famotidine for acid reflux usually starts to ease symptoms within about 30–60 minutes, with stronger relief over the next 1–3 hours, and its acid‑reducing effect can last roughly 10–12 hours depending on the dose and your condition. For chronic reflux (GERD), it often takes several days to a few weeks of regular dosing to feel consistent improvement, even though each individual dose begins working the same day.

How fast it starts working

For occasional heartburn or mild acid reflux, symptom relief typically begins within about 1 hour after taking an oral dose.

Pharmacology data show onset of action around 60–90 minutes, with peak acid‑suppression effects at about 1–3 hours.

If you use a combo product like famotidine plus antacid (such as Pepcid Complete), the antacid part can calm burning more quickly while famotidine ramps up in the background.

What that feels like in real life

Many people notice burning or sour‑taste relief gradually fading over the first couple of hours rather than instantly.
Night‑time reflux often improves when a dose is taken in the evening, but you might still have some symptoms the first nights until a routine is established.

How long it lasts

Standard over‑the‑counter doses (10–20 mg) usually reduce acid for about 10–12 hours.

Prescription regimens for GERD often use 20–40 mg twice daily, aiming for near‑continuous acid reduction over weeks to allow the esophagus to heal.

Short‑term vs long‑term effect

Short‑term: each dose works the same day, with noticeable symptom relief in the first hours if the reflux is mild to moderate.

Long‑term: healing of inflammation or erosive esophagitis can take 6–12 weeks of regular therapy, so deep, lasting improvement is not instant even though doses are working in the background.

Tips for timing and use

For predictable “trigger” meals, taking famotidine about 15–60 minutes before eating can reduce the chance of symptoms.

For GERD, clinicians often recommend one dose in the morning and one at bedtime to cover both daytime and night‑time reflux.

If you need very fast relief right now, a simple antacid (chewable or liquid) can be combined with famotidine as directed on the package or by a clinician, because antacids act within minutes while famotidine takes longer to kick in.

When it might seem “too slow”

Very severe reflux, large meals late at night, or lying down soon after eating can overwhelm what a single dose can handle, making it feel like the medicine is “not working yet.”
If there is significant esophageal damage (like erosive esophagitis), pain and burning can persist for days to weeks even though acid levels are already lower.

Red‑flag symptoms: get urgent care

Contact a doctor or emergency service promptly if you notice:

Trouble swallowing, chest pain, or pain spreading to arm, jaw, or back.
Vomiting blood, black or tarry stools, unintentional weight loss, or persistent vomiting.

These can signal conditions that need more than famotidine alone. TL;DR: Famotidine usually starts working for acid reflux within about an hour, peaks in a few hours, and each dose can control acid for roughly half a day, but meaningful healing of chronic reflux often takes regular use over several days to weeks.

Information gathered from public forums or data available on the internet and portrayed here.