Zantac | Ranitidine

Medication class: Histamine-2 Receptor Blocker
Manufacturer: GlaxoSmithKline
Approval date: October, 1984

What is Zantac and how does it work

The active ingredient in Zantac is ranitidine, an antihistamine that reduces production of stomach acid by blocking the effect of histamine on acid producing cells in the stomach. Histamine is a natural chemical that stimulates stomach cells to produce acid. Excessive amounts of acid can damage the stomach, esophagus and duodenum, producing inflammation and ulcers. Zantac prevents ulcers, reduces sypmtoms of ulcers (pain, bleeding, burning, weight loss, vomiting) and helps ulcers heal by reducing the production of acid.

What does Zantac treat

• Ulcers in the stomach and duodenum (intestines)
• Zollinger-Ellison syndrome (severe excessive secretion of acid)
• Inflammation and heartburn caused when gastric acid from the stomach flows into the esophagus (gastroesophageal reflux disease or GERD)
• Esophagitis (inflammation of the esophagus due to acid reflux)
• Occasional heartburn after a meal

How effective is Zantac

• Active Duodenal ulcers: Patients treated with 100 mg twice daily for 4 weeks reported a reduction in daytime and night-time pain and consumed less antacids than those treated with placebo.
• Healing Duodenal ulcers: A single 150 mg dose at bedtime significantly reduced the number of ulcers and prevented the recurrence of ulcers more than placebo, over a 12-month period.
• Gastric ulcer: 68% of outpatients treated with 150 mg over a period of 6 weeks were pain free compared to 51% treated with placebo. In another 12-month long study, Zantac 150 mg taken once during bedtime was more effective at maintaining healing of gastric ulcers than placebo.
• Pathological Hypersecretory Conditions (Zollinger-Ellison syndrome): Zantac reduced gastric acid secretions and the occurrence of diarrhea, anorexia and ulcer pain in outpatients as compared to placebo. Ulcers healed in 42% of patients.
• Gastroesophageal Reflux Disease (GERD): Zantac 150 mg taken twice daily for 6 weeks was more effective than placebo in relieving heartburn and other symptoms of GERD. Additionally, patients taking Zantac consumed significantly less antacids than those treated with placebo. Benefit was evident within 1 to 2 weeks.
• In a 2-week study of patients with heart burn, Zantac was effective in providing relief within 24 hours of initiation of therapy.
• Erosive esophagitis (inflammation of esophagus): In two 12 week trials, Zantac 150 mg given 4 times daily healed ulcers in 84% of patients.

What are interesting facts about Zantac

• Zantac can heal duodenal ulcers within 4 weeks and stomach ulcers with 6 weeks.
• Zantac is safe and effective for children between the age groups of 1 month – 16 years of age.
• Zantac is available over the counter for occasional heart burn.
• Generic versions are available.

How is Zantac dosed and administered

Zantac is available as tablets Zantac 150 mg, 300 mg, Zantac 75 mg, 25 mg), Syrup 15mg/mL, and injection 25 mg/ml.

• Active duodenal ulcers: the recommended oral is 150 mg twice daily or 300 mg at bedtime or after the evening meal.
• Zollinger Ellison Syndrome: the recommended adult oral dosage is 150 mg twice daily. Up to 6 grams a day has been used for severe disease.
• Gastric ulcers: 150 mg orally twice daily to treat gastric ulcers. The recommended maintenance dosage for healing of gastric ulcers is 150 mg taken at bedtime.
• Gastresophageal Reflux Disease: the recommended adult oral dosage is 150 mg twice daily.
• Erosive Esophagitis: 150 mg 4 times daily for initial treatment and 150 mg twice daily for maintenance.
• Occassional heartburn: 75 or 150 mg once or twice daily 30-60 minutes before ingesting meals or beverages that cause heartburn. Self treatment should not last longer than 2 weeks.
• Gastric or duodenal ulcers (pediatric): 2 to 4 mg/kg twice daily up to 300 mg daily for initial treatment then 2 to 4 mg/kg once daily up to 150 mg daily for maintenance.
• Gerd or erosive esophagitis (pediatric): 5 to 10 mg/kg/day in two divided doses.

What are the side effects of Zantac

Common: constipation, diarrhea, muscle aches, nausea, vomiting, headache, fatigue, confusion, dizziness, rash.

Serious: Liver dysfunction, hallucinations, reduced blood cells, pancreatitis, pneumonia, allergic reactions.

Zantac drug interactions

• Reyataz (atazanavir): Zantac may impair absorption of Reyataz by decreasing stomach acid.
• Glucotrol (glipizide): In diabetic patients, a single oral dose of 150 mg of Zantac decreased absorption of Glipizide by 34%.
• Ketoconazole: Ketoconazole requires gastric acid to work effectively. If administered with Zantac the absorption of ketoconazole may be reduced by almost 95%, rendering it ineffective.
• Versed (midazolam) and Halcion (triazolam): Zantac combined with midazolam or triazolam may increase the absorption of each drug by 65% and 30%, respectively. Excessive or prolonged sedation may occur.

References: Zantac FDA Prescribing Information.

Author: Omudhome Ogbru, PharmD

This medication summary is for information only and is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider.