Zantac 360
Zantac 360 is a US over-the-counter acid reducer. Zantac 360 is used for Relief of heartburn, Prevention of heartburn and Prescription uses are different.
Also called: Acid Controller (United States) · Acid (Canada) · Ausfam (Australia)
Pronunciation: pronunciation varies by local usage.
- Generic name
- famotidine
- Brand names
- Zantac 360
- Drug class
- H2 blocker (histamine-2 receptor antagonist); acid reducer
- Form
- Tablet. Zantac 360 OTC Drug Facts label: famotidine USP 20 mg in each tablet.
- Route
- Oral
- Legal status
- US over-the-counter (OTC) drug. Legal status outside the United States is not covered by the sources reviewed (gap).
Availability and supply rules vary by country
Trade names by country: United States · Canada · Australia · India · Nepal
Australia: Ausfam · Full directory
What famotidine is and how it works
Zantac 360 is a US over-the-counter acid reducer. Each tablet contains famotidine USP 20 mg. Famotidine is in a class of medicines called H2 blockers; it works by decreasing the amount of acid made in the stomach. The product is labelled to relieve heartburn associated with acid indigestion and sour stomach, and to prevent heartburn associated with acid indigestion and sour stomach brought on by eating or drinking certain food and beverages. The older ranitidine-containing Zantac was withdrawn in the US in 2020 and is not this product. (1) (2)
The OTC label is written for adults and children 12 years and over, allows no more than 2 tablets in 24 hours, and directs people to consult a doctor if heartburn continues or worsens or if the product is needed for more than 14 days. Self-treatment is for occasional heartburn; persistent symptoms or alarm features (for example trouble or pain swallowing food, vomiting with blood, or bloody or black stools) need medical assessment rather than an acid reducer. This page is general information, not a diagnosis or a treatment plan.
Mechanism of action: how famotidine works
Famotidine is in a class of medications called H2 blockers (histamine-2 receptor antagonists). It works by decreasing the amount of acid made in the stomach. (1) (2) (3)
What is Famotidine used for?
Relief of heartburn
The OTC label states that the product relieves heartburn associated with acid indigestion and sour stomach. (1)
Prevention of heartburn
The OTC label states that the product prevents heartburn associated with acid indigestion and sour stomach brought on by eating or drinking certain food and beverages. For prevention it is taken before eating or drinking the trigger food or beverage (label window: 10 to 60 minutes before; the MedlinePlus patient information describes a 15 to 60 minute window for OTC famotidine generally). (1) (2)
Prescription uses are different
Prescription famotidine is used to treat ulcers (sores on the lining of the stomach or small intestine), gastroesophageal reflux disease (GERD, in which backward flow of acid from the stomach causes heartburn and injury of the esophagus), and conditions where the stomach produces too much acid, such as Zollinger-Ellison syndrome. These are prescription uses and are not Zantac 360 OTC uses. (2)
Before taking famotidine
Do not take / not appropriate for
- Do not use if you are allergic to famotidine or other acid reducers. The prescription product information states that famotidine is contraindicated in patients with a history of serious hypersensitivity reactions (for example anaphylaxis) to famotidine or other histamine-2 receptor antagonists. (all users) (1) (3)
- Do not use if you have trouble or pain swallowing food, vomiting with blood, or bloody or black stools. These may be signs of a serious condition; the label directs the person to see a doctor. (all users) (1)
- Do not use with other acid reducers. (all users) (1)
Tell your clinician about
- Heartburn lasting over 3 months (the label notes this may be a sign of a more serious condition).
- Heartburn with lightheadedness, sweating, or dizziness.
- Chest pain or shoulder pain with shortness of breath, sweating, pain spreading to the arms, neck or shoulders, or lightheadedness; frequent chest pain.
- Frequent wheezing, particularly with heartburn.
- Unexplained weight loss.
- Nausea or vomiting, or stomach pain.
- Kidney disease.
- Any prescription medicine the person is taking: the label says acid reducers may interact with certain prescription drugs, so ask a doctor or pharmacist before use.
- Pregnancy or breastfeeding: the label says to ask a health professional before use.
- Allergy history: the patient information advises telling your doctor and pharmacist if you are allergic to famotidine, cimetidine (Tagamet), nizatidine (Axid), ranitidine (Zantac), or any other medications.
- That the intended user is a child under 12 years: the label says to ask a doctor.
- Phenylketonuria (PKU), or a history of trouble swallowing or kidney disease, per the prescription patient information.
Famotidine dosage and how to take it
- Adults and children 12 years and over, to relieve symptoms: swallow 1 tablet with a glass of water. Do not chew the tablet.
- To prevent symptoms: swallow 1 tablet with a glass of water at any time from 10 to 60 minutes before eating food or drinking beverages that cause heartburn.
- Do not use more than 2 tablets in 24 hours.
- Children under 12 years: ask a doctor. The sources reviewed contain no OTC Zantac 360 dose for children under 12 (gap).
- Read the directions and warnings before use.
- Take famotidine exactly as directed on the label; do not take more or less of it, or more often, or for a longer time than the label (or a prescriber, for prescription famotidine) directs.
- The label states that heartburn continuing or worsening, or needing to take the product for more than 14 days, requires consulting a doctor; let the clinician you see advise on whether to continue or stop the product rather than making that decision yourself.
- If you have any of the alarm symptoms listed above (trouble or pain swallowing food, vomiting with blood, or bloody or black stools), do not self-treat with this product and seek medical assessment.
- Do not take an extra dose or exceed the labelled maximum in 24 hours; any dose or treatment change should be decided by a clinician.
- Do not let anyone else take your medicine.
Procedures and treatment changes
Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3)
Missed dose
Over-the-counter famotidine is usually taken as needed. If a doctor has advised taking it regularly, the patient information says to take the missed dose as soon as it is remembered, but to skip it if the next dose is almost due and continue the regular schedule. Do not take an extra dose to make up for a missed one; ask the prescriber or pharmacist if unsure.
Overdose
In case of overdose, get medical help or contact a Poison Control Center right away; the US OTC label gives 1-800-222-1222. The patient information also directs calling the poison control helpline at 1-800-222-1222, and states that if the person has collapsed, had a seizure, has trouble breathing, or cannot be awakened, emergency services should be called immediately (911 in the US). The prescription product information states that the types of adverse reactions in overdosage are similar to those seen at recommended doses, and that treatment is symptomatic and supportive: unabsorbed material may be removed from the gastrointestinal tract, the patient monitored, and supportive therapy employed. Famotidine is eliminated by hemodialysis because of low plasma-protein binding, although experience with hemodialysis as a treatment for famotidine overdosage is limited. (1) (2) (3)
Famotidine side effects
Famotidine may cause side effects. Most reported effects are mild, but uncommon serious reactions have been reported. The information below covers OTC and prescription famotidine; prescription doses and monitored settings differ from OTC self-treatment.
Headache or dizziness
What to notice: Headache and dizziness occurred in greater than or equal to 1% of famotidine-treated patients in clinical trials, and are also listed in the patient information.
What to do: Tell your doctor if the symptom is severe or does not go away; do not change your treatment yourself. (2) (3)
Constipation or diarrhea
What to notice: Constipation occurred in greater than or equal to 1% of famotidine-treated patients in clinical trials; the patient information lists both constipation and diarrhea as possible side effects.
What to do: Tell your doctor if the symptom is severe or does not go away; do not change your treatment yourself. (2) (3)
Fussiness in babies
What to notice: The patient information lists fussiness in babies who take famotidine. This applies to prescribed use in infants, not to OTC self-treatment.
What to do: Discuss with the prescribing clinician; do not adjust an infant's treatment yourself. (2)
Hypersensitivity reaction
What to notice: Hives, skin rash, itching, swelling of the face, throat, tongue, lips, eyes, hands, feet, ankles, or lower legs, hoarseness, difficulty breathing or swallowing.
What to do: The patient information says these symptoms are uncommon but to call your doctor immediately if any occur. Severe reactions such as breathing difficulty or throat swelling require emergency care. (2)
Central nervous system adverse reactions
What to notice: Confusion, delirium, hallucinations, disorientation, agitation, seizures, and lethargy; reported in elderly patients and patients with moderate and severe renal impairment treated with famotidine.
What to do: Seek prompt medical assessment. Famotidine blood levels are higher in renal impairment and dosage adjustment is recommended for prescription use. (3)
Other uncommon reactions reported after approval
What to notice: Arrhythmia, AV block, prolonged QT interval; cholestatic jaundice and hepatitis; agranulocytosis, pancytopenia, leukopenia; anaphylaxis, angioedema, facial edema, urticaria; rhabdomyolysis and muscle cramps; confusion, agitation, paresthesia; interstitial pneumonia; toxic epidermal necrolysis/Stevens-Johnson syndrome.
What to do: These reactions are reported voluntarily and frequency cannot be estimated, but serious symptoms require prompt medical assessment and, for severe reactions, emergency care. (3)
Serious warnings
Serious hypersensitivity / anaphylaxis — emergency
Symptoms: Hives, rash, itching, swelling of the face, throat, tongue, lips, eyes, hands, feet, ankles, or lower legs, hoarseness, difficulty breathing or swallowing.
Action: Seek emergency care for breathing difficulty, throat or tongue swelling, or collapse. Famotidine is contraindicated in patients with a history of serious hypersensitivity reactions to famotidine or other H2 receptor antagonists, and the OTC label says do not use if allergic to famotidine or other acid reducers. (2) (3) (1)
Alarm gastrointestinal symptoms — urgent_medical_review
Symptoms: Trouble or pain swallowing food, vomiting with blood, or bloody or black stools.
Action: The label says these may be signs of a serious condition and directs the person to see a doctor; do not self-treat with an acid reducer. Seek medical assessment. (1)
Chest pain or cardiac-type symptoms — emergency
Symptoms: Chest pain or shoulder pain with shortness of breath, sweating, pain spreading to the arms, neck or shoulders, or lightheadedness; frequent chest pain.
Action: The label directs asking a doctor before use when these symptoms are present. Symptoms of this kind need urgent medical assessment rather than treatment with an acid reducer; use emergency services for severe or worsening chest pain or breathing difficulty. (1)
Central nervous system reactions in older adults and renal impairment — urgent_medical_review
Symptoms: Confusion, delirium, hallucinations, disorientation, agitation, seizures, and lethargy; also prolonged QT intervals reported in patients with moderate and severe renal impairment.
Action: Seek prompt medical assessment. These reactions have been reported in elderly patients and in patients with moderate and severe renal impairment treated with famotidine, in whom blood levels are higher and dosage adjustment is recommended for prescription use. (3)
Possible gastric malignancy — urgent_medical_review
Symptoms: Suboptimal response to therapy or early symptomatic relapse after completing treatment in adults.
Action: The prescription product information states that symptomatic response to famotidine does not preclude the presence of gastric malignancy; evaluation for gastric malignancy should be considered in adults with a suboptimal response or early symptomatic relapse. Persistent or worsening heartburn should be reviewed by a clinician. (3) (1)
Interactions
| Medicine or test | Effect | Action |
|---|---|---|
| Other acid reducers and nonprescription heartburn medicines | The OTC label says do not use with other acid reducers. The patient information lists other medicines for heartburn among nonprescription products that may interact with famotidine, and advises discussing them with a doctor or pharmacist before starting. | Do not combine with other acid reducers; give the pharmacist a complete list of heartburn medicines before use. (1) (2) |
| Prescription medicines generally | The OTC label states that acid reducers may interact with certain prescription drugs. | Ask a doctor or pharmacist before use if taking a prescription drug, and provide a complete medicine, vitamin, supplement, and herbal list. (1) (2) |
| Drugs dependent on gastric pH for absorption | Systemic exposure of the concomitant drug may be significantly reduced, leading to loss of efficacy. | A prescriber or pharmacist should review the full medicine list for pH-dependent drugs before use. (3) |
| Tizanidine (CYP1A2 substrate) | Potential for substantial increases in blood concentrations of tizanidine, resulting in hypotension, bradycardia, or excessive drowsiness. | Avoid concomitant use if possible; discuss alternatives with the prescriber. (3) |
| Other H2 blockers and related allergy history | The patient information advises telling your doctor and pharmacist if you are allergic to famotidine, cimetidine (Tagamet), nizatidine (Axid), ranitidine (Zantac), or any other medications. | Disclose allergy history and any previous reaction to acid reducers before use. (2) |
Pregnancy, breastfeeding, kidney/liver function, age
Children
Zantac 360 is labelled for adults and children 12 years and over. For children under 12 years the label says to ask a doctor. The sources reviewed contain no OTC Zantac 360 dosing for children under 12 (gap). Prescription famotidine dosing in the prescribing information is for patients 40 kg and over and is not an OTC dose. (1) (3)
Pregnancy
The OTC label says that if pregnant or breastfeeding, ask a health professional before use. The prescription product information states that available data with H2 receptor antagonists, including famotidine, in pregnant women are insufficient to establish a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes; animal reproduction studies showed no significant evidence of impaired fertility or harm to the fetus at the doses studied, but there are no adequate or well-controlled studies in pregnant women, and the drug should be used during pregnancy only if clearly needed. Discussion of need and alternatives belongs with the clinician. (1) (3)
Breastfeeding
The OTC label says to ask a health professional before use. The prescription product information states that there are limited data on the presence of famotidine in human breast milk, that there were no effects on the breastfed infant, and that there are no data on famotidine effects on milk production; the developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for famotidine and any potential adverse effects on the breastfed child. (1) (3)
Kidney disease / renal impairment
The OTC label directs people with kidney disease to ask a doctor before use. For prescription famotidine, no dosage adjustment is needed in mild renal impairment (creatinine clearance greater than or equal to 60 mL/minute), and dosage reduction is recommended for adults and pediatric patients 40 kg or greater with moderate or severe renal impairment (creatinine clearance less than 60 mL/minute); CNS adverse reactions and prolonged QT intervals have been reported in patients with moderate and severe renal impairment, and famotidine clearance is reduced in these groups. These prescription recommendations are not Zantac 360 OTC doses. (1) (3)
Older adults
Central nervous system adverse reactions, including confusion, delirium, hallucinations, disorientation, agitation, seizures, and lethargy, have been reported in elderly patients treated with famotidine. Older adults and their clinicians should weigh self-treatment against medical review, particularly if kidney function is reduced. (3)
Monitoring
Before starting
- Check for alarm features that the label says make the product unsuitable for self-treatment: trouble or pain swallowing food, vomiting with blood, or bloody or black stools.
- Check the duration of heartburn (over 3 months is flagged by the label as possibly indicating a more serious condition) and any associated symptoms such as lightheadedness, sweating, dizziness, chest or shoulder pain with shortness of breath, frequent chest pain, frequent wheezing with heartburn, unexplained weight loss, nausea or vomiting, or stomach pain.
- Confirm no allergy to famotidine or other acid reducers, and no history of serious hypersensitivity to famotidine or other H2 receptor antagonists.
- Review all prescription and nonprescription medicines, including other acid reducers and pH-dependent drugs, with a doctor or pharmacist.
- Check for kidney disease, and for pregnancy or breastfeeding, which the label says require asking a health professional before use.
- Confirm the user is an adult or a child 12 years and over; children under 12 require asking a doctor.
During treatment
- Limit use to no more than 2 tablets in 24 hours.
- Reassess if heartburn continues or worsens, or if the product is needed for more than 14 days; the label directs consulting a doctor in these situations, and the clinician should advise on whether to continue.
- Watch for hypersensitivity symptoms and for central nervous system symptoms (especially in older adults and people with renal impairment), seeking medical assessment promptly if they occur.
- Record any unusual or severe effect, and consider reporting a serious side effect to the FDA MedWatch program (online at https://www.fda.gov/Safety/MedWatch or by phone at 1-800-332-1088).
- Keep all appointments with your doctor and keep a written list of all medicines, vitamins, minerals, and dietary supplements being taken.
Storage
Store at 20-25 °C (68-77 °F) and protect from moisture, per the OTC label. Keep the medication in the container it came in, tightly closed, and out of reach of children; store at room temperature and away from excess heat and moisture (not in the bathroom). The liquid-freeze and 30-day liquid disposal instructions in the patient information apply to famotidine liquid products, not to these tablets.
Professional information
Clinician-facing context only. Use the current local product label for Zantac 360, and the separate prescription famotidine product information where relevant; the prescription doses are not Zantac 360 OTC doses.
United States (OTC)
Indication: Heartburn associated with acid indigestion and sour stomach - relief or prevention
Dose summary: Adults and children 12 years and over: to relieve symptoms, swallow 1 tablet (famotidine USP 20 mg) with a glass of water, do not chew; to prevent symptoms, swallow 1 tablet with a glass of water at any time from 10 to 60 minutes before eating food or drinking beverages that cause heartburn. Do not use more than 2 tablets in 24 hours. Children under 12 years: ask a doctor (no OTC dose in the sources reviewed - gap). The label directs consulting a doctor if heartburn continues or worsens or if the product is needed for more than 14 days.
Renal context: The OTC label directs people with kidney disease to ask a doctor before use. For prescription famotidine, no dosage adjustment is needed in mild renal impairment (creatinine clearance greater than or equal to 60 mL/minute), and dosage reduction is recommended in adults and pediatric patients 40 kg or greater with moderate or severe renal impairment (creatinine clearance less than 60 mL/minute); CNS adverse reactions and prolonged QT intervals have been reported in moderate and severe renal impairment. These prescription recommendations are not Zantac 360 OTC doses. (1) (2) (3)
Hepatic guidance
The research notes reviewed do not include hepatic impairment dosing or warnings for famotidine. This remains a gap and must be resolved from local product information before publication.
Overdose note
The types of adverse reactions in famotidine overdosage are similar to those encountered at recommended dosages. Management is symptomatic and supportive: unabsorbed material should be removed from the gastrointestinal tract, the patient monitored, and supportive therapy employed. Due to low binding to plasma proteins, famotidine is eliminated by hemodialysis, although experience on its usefulness in overdosage is limited. (1) (2) (3)
Frequently asked questions
Is Zantac 360 the same medicine as the old Zantac?
No. Zantac 360 contains famotidine 20 mg per tablet. The older ranitidine-containing Zantac was withdrawn in the US in 2020 and is not this product. (1)
How long can I take Zantac 360 for heartburn?
The label allows no more than 2 tablets in 24 hours and directs you to consult a doctor if your heartburn continues or worsens, or if you need to take the product for more than 14 days. Let the clinician you see advise on whether to continue rather than deciding on your own. (1)
What if I have trouble swallowing, vomit blood, or have black stools?
Do not use this product for those symptoms. The label says these may be signs of a serious condition and directs you to see a doctor. Seek medical assessment. (1)
Can I take it with another heartburn medicine?
The label says do not use with other acid reducers, and says to ask a doctor or pharmacist before use if you are taking a prescription drug because acid reducers may interact with certain prescription drugs. (1)
Does Zantac 360 treat ulcers or GERD?
No. Those are prescription uses of famotidine. The OTC product is labelled to relieve and prevent heartburn associated with acid indigestion and sour stomach; a clinician must assess persistent symptoms. (2) (1)
What is the mechanism of action of famotidine?
Famotidine is in a class of medications called H2 blockers (histamine-2 receptor antagonists). It works by decreasing the amount of acid made in the stomach. (1) (2) (3)
References
- Zantac 360 (famotidine) tablet, film coated — Drug Facts labelU.S. National Library of Medicine, DailyMed · United States · accessed 2026-10-13 · source 1
- Famotidine: MedlinePlus Drug InformationMedlinePlus, U.S. National Library of Medicine · United States · accessed 2026-10-13 · source 2
- Famotidine tablets, film coated — prescribing information (Aphena Pharma)U.S. National Library of Medicine, DailyMed · United States · accessed 2026-10-13 · source 3
Brand names by country
Single-ingredient famotidine names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.
Priority countries
United States
- acid controllertablet, film coated · 20 mg, 10 mg · h e bregulator source
- heartburn relieftablet, film coated, tablet · 10 mg, 20 mg · shield pharmaceuticals corpregulator source
- Zantac 360tablet, film coated · 20 mg · lil' drug store products, incregulator source
- Pepcid ACtablet, film coated · 20 mg, 10 mg · kenvue brands llcregulator source
- dg health heartburn preventiontablet, film coated · 20 mg, 10 mg · dolgencorp incregulator source
- equaline heartburn preventiontablet, film coated · 20 mg, 10 mg · united natural foods, inc. dba unfiregulator source
- Pepcidtablet, film coated · 20 mg, 40 mg · bausch health us llcregulator source
- signature care acid controllertablet, film coated · 10 mg, 20 mg · safewayregulator source
- Welmate Famotidine 10mgtablet · 20 mg, 10 mg · yyba corpregulator source
- basic care heartburn preventiontablet, film coated · 20 mg · amazon.com services llcregulator source
Canada
- ACIDregulator source
- FAMOTIDINE OMEGAregulator source
- PEPCID ACregulator source
- MAXIMUM STRENGTH PEPCID ACregulator source
Australia
- Ausfamreference source
India
Source-listed products; local stock and regulatory approval have not been confirmed. Check the exact ingredient, strength, and formulation with a pharmacist.
- Famonext 20 TabletTablet · 20mg · Cadila Pharmaceuticals Ltdpharmacy source recorded · checked 2026-09-24
- Famocid 40 TabletTablet · 40mg · Sun Pharmaceutical Industries Ltdpharmacy source recorded · checked 2026-09-24
- Famtac TabletTablet · 40mg · Abbottpharmacy source recorded · checked 2026-09-24
- FM 40mg TabletTablet · 40mg · Caplet India Pvt Ltdpharmacy source recorded · checked 2026-09-24
- Famolet 40mg Gelatin Coated TabletGelatin Coated Tablet · 40mg · Universal Drug House Pvt Ltdpharmacy source recorded · checked 2026-09-24
Nepal
Source-listed products; local stock and regulatory approval have not been confirmed. Check the exact ingredient, strength, and formulation with a pharmacist.
- FadineTablet · 40mg · Aristo Pharmaceuticals Ltd.reference source · checked 2026-09-24
- FAM H2Tablet · 20mg · Ozone Pharmaceuticals Ltd.reference source · checked 2026-09-24
- FAM OTablet · 20mg · Omnica Laboratories Pvt. Ltd..reference source · checked 2026-09-24
- FamocidTablet · 20mg · Sun Pharmaceutical Industries Ltd.reference source · checked 2026-09-24
- FamonitTablet · 20mg · Zydus Pharmaceuticalsreference source · checked 2026-09-24
- FamotinTablet · 20mg · Usv Ltd.reference source · checked 2026-09-24
- FampepTablet · 20mg · Seagull Labs (I) Pvt Ltdreference source · checked 2026-09-24
- FamtacTablet · 20mg · Abbott India Ltd.reference source · checked 2026-09-24
View brands in additional countries.
Philippines
H2 Bloc