Gaster 10 S Tablets
ใฌในใฟใผ10 S้
H2 blocker (famotidine), reduces stomach acid
Fast-dissolving tablets
Stomach pain, heavy stomach feeling, heartburn, and queasiness (feeling sick to your stomach). This product contains an H2 blocker. Do not take it for symptoms other than these.
Active Ingredients (per 1 tablet)
Famotidine 10 mg
Inactive Ingredients
Ethyl cellulose, cetanol, sodium lauryl sulfate, triacetin, cyclodextrin, flavor, l-menthol, D-mannitol, aspartame (L-phenylalanine compound), powdered starch syrup, calcium stearate
Instructions for Use
- โTake when stomach pain, heavy stomach feeling, heartburn, or queasiness appears. Let the tablet dissolve in your mouth and swallow it, or take it with water or lukewarm water.
| Age | Dose per use | Times per day |
|---|---|---|
| Adults (15 to 79 years) | 1 tablet | Up to 2 times daily |
| Under 15 years | Do not use | โ |
| 80 years and older | Do not use | โ |
- โIf symptoms have not settled 8 hours or more after taking it, take 1 more tablet.
- โIf your symptoms clear up, stop taking it.
- โFollow the recommended dosage strictly.
- โThe tablet breaks down easily in the mouth, but the medicine is not absorbed through the lining of the mouth. After it dissolves, swallow it with saliva, or with water or lukewarm water. Swallowing it whole with water or lukewarm water, like a normal tablet, works just as well.
- โAvoid alcoholic drinks when taking this product. (Medicines are generally not taken with alcohol.)
- โTo remove a tablet from the PTP sheet, press firmly on the raised side of the sheet with your fingertip to break the aluminum foil on the back, then take out the tablet. Do not swallow the PTP sheet, as it may puncture the esophageal lining and cause serious injury.
- โDo not use this product if you:
- (1) Have ever had an allergic reaction (such as rash, redness, itching, or swelling of the throat, eyelids, or lips) to famotidine or another H2 blocker.
- (2) Are being treated at a medical institution for any of the following diseases, or are being given any of the following medicines there:
- Diseases: blood disease, kidney or liver disease, heart disease, stomach or duodenal disease, or an immune system disease such as asthma or rheumatism
- Medicines: steroids, antibiotics, anticancer drugs, or azole antifungals
- (This product may lower white blood cells or platelets.)
- (With kidney or liver disease, the medicine leaves the body more slowly, so its effects may be stronger.)
- (With heart disease such as a heart attack, valve disease, or cardiomyopathy, an irregular pulse with an abnormal ECG may appear.)
- (People being treated for stomach or duodenal disease are likely to have been prescribed famotidine or a similar medicine, so take care not to take it twice.)
- (This product lowers the absorption of azole antifungals and weakens their effect.)
- (3) Have been told by a doctor that you have a blood abnormality, such as a low red blood cell count (anemia), a low platelet count (bleeding easily, or bleeding that is hard to stop), or a low white blood cell count. (This product may trigger a blood abnormality again.)
- (4) Have phenylketonuria. (This product contains an L-phenylalanine compound.)
- (5) Are under 15 years of age, or are 80 years of age or older.
- (6) Are pregnant or possibly pregnant.
- โDo not take any other stomach and intestinal medicine while taking this product.
- โDo not take this product while breastfeeding. If you take it, avoid breastfeeding.
- โDo not take for more than 2 weeks in a row. (You may overlook a serious digestive disease, so see a doctor.)
- โSeek immediate medical attention if any of the following serious symptoms appear:
- โข Shock (anaphylaxis): Itching of skin, hives, hoarseness, sneezing, itchy throat, difficulty breathing, palpitations, or clouded consciousness immediately after use.
- โข Stevens-Johnson syndrome / toxic epidermal necrolysis: High fever, redness of eyes, eye discharge, sores on lips, sore throat, or widespread rash or redness on skin that persists or rapidly worsens.
- โข Rhabdomyolysis: Pain in the muscles of the limbs, shoulders, or lower back, numbness or weakness in the limbs, stiffness, general fatigue, or reddish-brown urine.
- โข Liver disorder: Fever, itching, rash, jaundice (yellowing of the skin or whites of the eyes), dark urine, general fatigue, or loss of appetite.
- โข Kidney disorder: Fever, rash, decreased urine output, swelling throughout the body, general fatigue, joint pain, or diarrhea.
- โข Interstitial pneumonia: Shortness of breath with climbing stairs or slight exertion, dry cough, fever, or other symptoms that appear suddenly or persist.
- โข Blood disorder: Sore throat, fever, general fatigue, pale face or inner eyelids, easy bleeding (bleeding gums, nosebleed), or bruising that does not fade when pressed.
- โ Consult a doctor or pharmacist before use if you:
- (1) Are under medical treatment, or are taking other medicines.
- (2) Have ever had an allergic reaction to a medicine.
- (3) Are elderly (65 years or older). (Body functions are generally reduced in older people.)
- (4) Have any of the following symptoms: sore throat, cough, and high fever (these may be signs of a serious infection with a blood abnormality such as low blood cell counts; taking this product with these symptoms may make them worse and delay noticing its side effects); unexplained weight loss; or persistent abdominal pain (another illness may be the cause).
- โStop use immediately and consult a doctor or pharmacist โ bringing this package insert with you โ if any of the following appear after taking this product, as they may be side effects:
- Skin: Rash, redness, itching, or swelling
- Cardiovascular: Irregular pulse
- Nervous system: Feeling faint, or convulsions
- Other: Feeling unwell, tiredness, fever with a sore throat, or other changes in how you feel
- โIf you accidentally take more than the set dose, stop taking it immediately and consult a doctor or pharmacist, bringing this package insert with you.
- โStop use and consult a doctor or pharmacist โ bringing this package insert with you โ if the following symptoms persist or worsen: constipation, loose stools, diarrhea, or dry mouth.
- โStop use and consult a doctor or pharmacist โ bringing this package insert with you โ if symptoms do not improve after 3 days.
- โStore in a cool, dry place away from direct sunlight. Keep out of reach of children. Do not transfer to another container (this can cause mistaken use or affect quality). Do not use after the expiry date.
Additional Information
This medicine is taken when symptoms appear, not at set times. Food does not affect it, so you can take it before, after, or between meals. One tablet controls excess stomach acid for about 8 hours, so if you take it twice in a day, leave at least 8 hours between doses.
Contains famotidine, an ingredient used in prescription medicine (printed on the box). Unlike antacids that neutralize stomach acid, this H2 blocker controls excess stomach acid and helps the stomach lining recover.
Sources & Documents
- Japanese product page
- Japanese PDF
- Last verified: October 15, 2026
Related Medicines
For informational purposes only. Always consult a doctor or pharmacist before taking any medication.