Generic name: Ranitidine hydrochloride.

Zantac is an antiulcer medication. It blocks the effects of histamine in the stomach, which reduces stomach acid secretion.

Quick Facts About Zantac


Used for short-term therapy (4 to 8 weeks) to treat active duodenal (upper intestinal) ulcers, active benign stomach ulcers, and maintenance therapy for duodenal ulcers. Also used to treat Zollinger-Ellison syndrome (peptic ulcer with too much acid), mastocytosis, and gastroesophageal reflux disease (GERD). Also prescribed to prevent stomach and duodenum damage from long-term use of nonsteroidal antiinflammatory medications, and to treat bleeding of the stomach and intestine, and stress-induced ulcers.

Zantac Dosage

Take exactly as prescribed. Follow your doctor’s diet program.

  • Usual adult dose: for active duodenal ulcer — 150 milligrams taken 2 times per day or 10 milliliters (2 teaspoonfuls) taken 2 times per day for 4 to 8 weeks. Or doctor may suggest 300 milligrams or 20 milliliters (4 teaspoonfuls) at bedtime. Long-term use dosage is 150 milligrams per day or 10 milliliters (2 teaspoonfuls) per day, taken at bedtime. For Zollinger-Ellison syndrome and mastocytosis — 150 milligrams or 10 milliliters (2 teaspoonfuls) taken 2 times per day. For benign gastric ulcer and GERD — 150 milligrams or 10 milliliters (2 teaspoonfuls) taken 2 times per day for 6 to 8 weeks. For individuals with reduced kidney function — dose is adjusted by your doctor. Seniors — is individualized.
  • Usual child dose: not generally prescribed for children.
  • Missed dose: take as soon as possible, unless it is the next day. In that case, do not take the missed dose; go back to regular schedule. Do not double doses.

Zantac Side Effects

Overdose symptoms:

abnormal walking, low blood pressure, and exaggerated side effects. If you suspect an overdose, immediately seek medical attention.

More common side effects: headache (sometimes severe).

Less common or rare Zantac side effects: abdominal discomfort and pain, agitation, changes in blood count (anemia), changes in liver function, constipation, depression, diarrhea, difficulty sleeping, dizziness, hair loss, hallucinations, heart block, hepatitis, hypersensitivity reactions, inflammation of the pancreas, involuntary movements, irregular heartbeat joint pain, muscle pain, nausea and vomiting, rapid heartbeat, rash, reduced white blood cells, reversible mental confusion, sleepiness, slow heartbeat vague feeling of bodily discomfort vertigo, yellow eyes and skin.


Inform your doctor before combining Zantac with:

enoxacin (Penetrex), glipizide (Glucotrol), itraconazole (Sporanox), ketoconazole (Nizoral), midazolam (Versed), theophylline (Theo-Dur), triamterene (Dyrenium), warfarin (Coumadin).

Avoid alcohol when taking Zantac.

Special Cautions

If pregnant or planning to become pregnant, inform your doctor immediately. Appears in breast milk; could affect a nursing infant.

Seniors are prescribed Zantac according to individual needs.

Not generally prescribed for children.

  • Zantac assists in reducing the risk of duodenal ulcers recurring, and aids in the rapid healing of ulcers that occur during maintenance therapy.
  • Avoid if sensitive to or allergic to Zantac or similar medications.
  • Use with caution if you have kidney or liver disease.

Note: provides accurate and independent information prescription pills, over-the-counter medicines and natural products. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment. If you have questions about  dosage, or Zantac side effects, please contact your healthcare provider