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Drugs reference index «Zantac»



Generic name: Ranitidine hydrochlorideBrand names: Zantac

Why is Zantac prescribed?

Zantac is used to decrease the production of stomach acid, which may reduce irritation to the stomach lining and help heal ulcers and other gastrointestinal conditions. It's prescribed for the following:

  • Short-term treatment (4 to 8 weeks) of active ulcers, specifically duodenal ulcers or benign stomach ulcers (also called gastric ulcers).
  • Maintenance therapy (at a reduced dosage) to help keep the ulcer from coming back after it has healed.
  • Treatment of conditions in which the stomach produces too much acid, such as Zollinger-Ellison syndrome and systemic mastocytosis.
  • Treatment of gastroesophageal reflux disease (also known as GERD, which occurs when stomach acid backs up into the esophagus).
  • Treating and maintaining healing of erosive esophagitis (severe inflammation of the esophagus).

Two over-the-counter versions, Zantac 75 and Zantac 150, are also available for relieving and preventing heartburn, acid indigestion, and sour stomach. However, the prescription version is still needed for treatment of ulcers, esophagitis, GERD, and other conditions that require monitoring by a doctor.

Most important fact about Zantac

Zantac helps to prevent the recurrence of gastric or duodenal ulcers and aids the healing of ulcers that do occur.

How should you take Zantac?

Take Zantac exactly as prescribed by your doctor. Make sure you follow the diet your doctor recommends.

Dissolve effervescent tablets and granules in 6 to 8 ounces of water before taking them.

You can take an antacid for pain while you are taking Zantac.

  • If you miss a dose...Take it as soon as you remember. If it is almost time for your next dose, skip the one you missed and go back to your regular schedule. Never take 2 doses at the same time.
  • Storage instructions...Store Zantac at room temperature in the container it came in, tightly closed and away from moist places and direct light. Keep Zantac syrup from freezing.

What side effects may occur?

Side effects cannot be anticipated. If any develop or change in intensity, inform your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking Zantac.

  • Side effects may include:Headache, sometimes severe

Why should Zantac not be prescribed?

If you are sensitive to or have ever had an allergic reaction to Zantac or similar drugs, you should not take Zantac. Make sure that your doctor is aware of any drug reactions that you have experienced.

Special warnings about Zantac

A stomach malignancy could be present, even if your symptoms have been relieved by Zantac.

If you have kidney or liver disease, Zantac should be used with caution.

If you have phenylketonuria, you should be aware that the effervescent tablets and granules contain phenylalanine.

Possible food and drug interactions when taking Zantac

If Zantac is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining Zantac with the following:

AlcoholBlood-thinning drugsDiazepamDiltiazemEnoxacinGlipizideGlyburideItraconazoleKetoconazoleMetforminNifedipinePhenytoinProcainamideSucralfateTheophyllineTriazolam

Special information if you are pregnant or breastfeeding

The effects of Zantac in pregnancy have not been adequately studied. If you are pregnant or plan to become pregnant, inform your doctor immediately. Zantac appears in breast milk and could affect a nursing infant. If Zantac is essential to your health, your doctor may advise you to discontinue breastfeeding until your treatment with Zantac is finished.

Recommended dosage for Zantac


Active Duodenal Ulcer

The usual starting dose is 150 milligrams 2 times a day or 10 milliliters (2 teaspoonfuls) 2 times a day. Your doctor also might prescribe 300 milligrams or 20 milliliters (4 teaspoonfuls) once a day, after the evening meal or at bedtime, if necessary for your convenience. The dose should be the lowest effective dose. Long-term use should be reduced to a daily total of 150 milligrams or 10 milliliters (2 teaspoonfuls), taken at bedtime.

Other Excess Acid Conditions (such as Zollinger-Ellison Syndrome)

The usual dose is 150 milligrams or 10 milliliters (2 teaspoonfuls) 2 times a day. This dose can be adjusted upwards by your doctor.

Benign Gastric Ulcer and Gastroesophageal Reflux Disease (GERD)

The usual dose is 150 milligrams or 10 milliliters (2 teaspoonfuls) 2 times a day. Once an ulcer has cleared up, a single bedtime dose is prescribed to maintain healing. Symptoms of GERD generally improve within 24 hours after the start of therapy.

Erosive Esophagitis

The usual dose is 150 milligrams or 10 milliliters (2 teaspoonfuls) 4 times a day. Maintenance dosage is 150 milligrams or 10 milliliters (2 teaspoonfuls) twice a day.


Duodenal and Gastric Ulcers

For children 1 month to 16 years of age, the recommended dosage for initial treatment is 2 to 4 milligrams per 2.2 pounds of body weight per day twice daily up to a maximum of 300 milligrams per day. For long-term maintenance of healing, the recommendation is 2 to 4 milligrams per 2.2 pounds of body weight once daily up to a maximum of 150 milligrams per day.

Gastroesophageal Reflux Disease (GERD) and Erosive Esophagitis

For children 1 month to 16 years of age, the usual daily dosage is 5 to 10 milligrams per 2.2 pounds of body weight, divided into two doses.


People with kidney problems, such as some older adults, typically are given a lower dose. During the therapy with Zantac, the doctor is also more likely to monitor your kidney function if you're over 65.


Do not give Zantac 75 or Zantac 150 to children under 12 years old unless your doctor approves. Swallow tablets with a glass of water. Do not take more than 2 tablets a day or take them for longer than 2 weeks unless your doctor approves.

For Prevention of Heartburn Symptoms

Take 1 tablet with a glass of water 30 to 60 minutes before eating food or drinking beverages that could cause heartburn.

For Relief of Heartburn Symptoms

Take 1 tablet with a glass of water.


Any medication taken in excess can have serious consequences. If you suspect an overdose, seek medical attention immediately.

Information concerning Zantac overdosage is limited. However, an abnormal manner of walking, low blood pressure, and exaggerated side effect symptoms may be signs of an overdose.

If you experience any of these symptoms, notify your doctor immediately.

  • Zantac Prescribing Information (FDA)
  • Zantac Consumer Overview
  • Zantac MedFacts Consumer Leaflet (Wolters Kluwer)
  • Ranitidine Prescribing Information (FDA)
  • Ranitidine Professional Patient Advice (Wolters Kluwer)
  • Zantac 75 MedFacts Consumer Leaflet (Wolters Kluwer)

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