What to Know About Zantac (Ranitidine)

A Histamine Blocker That Reduces Stomach Acid

Table of Contents
View All
Table of Contents

April 1, 2020 Update: The Food and Drug Administration (FDA) announced the recall of all medications containing the ingredient ranitidine, known by the brand name Zantac. The FDA also advised against taking OTC forms of ranitidine, and for patients taking prescription ranitidine to speak with their healthcare provider about other treatment options before stopping medication. For more information, visit the FDA site.

Pharmacy customer discusses over the counter medication with pharmacist
SDI Productions / Getty Images

Zantac (ranitidine) is an over-the-counter drug most commonly used to treat gastroesophageal reflux disease (GERD). Ranitidine is also used to treat other conditions which involve an excess of stomach acid and can prevent the occurrence of stomach and intestinal ulcers. Ranitidine is a drug in the class of histamine-2 blockers and can be taken as a syrup or pill.

The most common brand name of ranitidine is Zantac, but it can also be found in stores under the labels Wal-Zan and Heartburn Relief. Due to the over-the-counter nature of this drug, many large retailers have developed their versions with ranitidine as the same primary ingredient.


FDA-approved uses of ranitidine include treatment of duodenal (intestinal) and gastric ulcers, GERD, and erosive esophagitis which have been diagnosed by endoscopy. Another diagnosis for which ranitidine is commonly used is for the treatment of Zollinger-Ellison syndrome, which causes excess production of stomach acid.

Ranitidine has been determined safe for short-term use in treating the aforementioned conditions. It is also safe for individuals to remain on a different dose of ranitidine long-term as part of a maintenance program for these conditions.

Off-Label Uses

One of the off-label uses of ranitidine is as a prophylactic treatment for stress ulcers. In a pediatric population, ranitidine is used off-label as a parenteral treatment for erosive esophagitis and GERD. Another off-label use for ranitidine is to treat erosive esophagitis in newborns.

Before Taking

Ranitidine is considered safe to use by most healthy people experiencing reflux and other acid-related symptoms, as it is available on an over-the-counter basis. This means it is considered a first-line treatment due to its availability.

Precautions and Contraindications

There are no contraindications associated with ranitidine. There are some precautions related to the use of ranitidine in pediatric and geriatric populations, as dosages must be adjusted to accommodate for absorption rates.

Healthcare providers should adjust the dosage of ranitidine in patients with impaired kidney and liver function, as absorption and elimination of the drug goes through these organs. Individuals with porphyria should use ranitidine with caution. Porphyria is a condition which causes excess protein buildup and ranitidine may cause an increase in the symptoms of porphyria. Patients with allergies to ranitidine should not use this drug in any amount.

Other Histamine-2 Antagonists

  • Axid
  • Axid AR
  • Axid Pulvules
  • Heartburn Relief
  • Pepcid
  • Pepcid AC
  • Tagamet
  • Tagamet HB
  • Zantac 150
  • Zantac 150 Efferdose
  • Zantac 25


It is recommended that patients with duodenal ulcers take 150 milligrams (mg) of ranitidine twice daily for short-term treatment. In patients who cannot remember to take a medication twice daily, this dosage can be adjusted to take 300 mg of syrup once daily after a meal. The recommended dosage for maintenance of healing duodenal ulcers is 150 mg once daily at bedtime. Patients who have GERD, hypersecretory conditions such as Zollinger-Ellison syndrome, and benign gastric ulcers should take ranitidine 150 mg twice daily.

Patients who have erosive esophagitis should take 150 mg of ranitidine four times daily. This dosage should be adjusted to 150 mg twice daily for patients who wish to maintain the healing process of erosive esophagitis.

All listed dosages are according to the drug manufacturer. Check your prescription and talk to your healthcare provider to make sure you are taking the right dose for you.


Pediatric patients wishing to treat GERD and erosive esophagitis must carefully calculate dosage based on body weight. The recommended formula is 5 to 10 mg per kilogram per day, which is usually divided into two doses.

For geriatrics or individuals with impaired kidney function, daily doses of Ranitidine should not exceed 150 mg.

How to Take and Store

It is acceptable to make up for missing a dose and no negative side effects should occur. However, take caution to ensure you do not exceed the maximum daily dosage in these instances.

In instances where overdosage has occurred, patients have experienced difficulty walking and a drop in blood pressure. This occurred in instances where up to 18 grams of ranitidine was taken orally.

In the event of overdosage, patients should seek medical care to remove the remaining ranitidine from their system. This will be followed by clinical monitoring and other therapies as needed.

Ranitidine syrup should be stored in an area kept between 39 F (4 C) and 77 F (25 C) in tight and light-resistant containers. Standard ranitidine pills should be stored in a dry, dark area kept between 60 F (15 C) and 86 F (30 C).

Side Effects


Common side effects associated with taking ranitidine include dizziness, nausea, vomiting, constipation, abdominal discomfort, muscle and joint pain, and rash. When patients with impaired kidney function ingested a dose that was too high, it resulted in sedation, confusion, agitation, and hallucinations. Research has shown these symptoms were minor and easily resolved with medical care.


Severe side effects associated with taking ranitidine include irregular heart rhythms, mixed hepatitis, blood count changes (such as leukopenia, granulocytopenia, and thrombocytopenia), gynecomastia, impotence, alopecia, vasculitis, and hypersensitive reactions such as anaphylaxis and angioneurotic edema. Contact your healthcare provider if you have any severe symptoms.

Warnings and Interactions

Ranitidine has been observed to have slight interactions with the blood-thinning medication warfarin. This has resulted in fluctuating levels of a blood test measuring prothrombin times.

Studies have been done verifying ranitidine did not harm rat and rabbit fetuses. However, these studies have not been replicated on human fetuses, making it advisable to discontinue if pregnant. If you are breastfeeding, talk to your healthcare provider before using ranitidine.

Ranitidine can have levels of toxic buildup in geriatric patients, those with poor kidney function, and pediatric patients. Ranitidine should be used with caution in these instances.

2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. U.S. National Library of Medicine, DailyMed. Ranitidine tablet [package insert].

  2. U.S. National Library of Medicine, DailyMed. Ranitidine syrup [package insert].

Additional Reading

By Brittany Ferri
Brittany Ferri, MS, OTR-L, CCTP, is an occupational therapist, consultant, and author specializing in psychosocial rehab.