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Ranitidine - Uses, Dosage, Side Effects, Drug Warnings, and Precautions

Published on Aug 02, 2022 and last reviewed on Oct 17, 2022   -  6 min read


Ranitidine is an acid-suppressing prescription drug used to treat heartburn and other gastric-associated conditions. Read the article for further details.

Ranitidine - Uses, Dosage, Side Effects, Drug Warnings, and Precautions


Ranitidine has been used in the treatment of GIT (gastrointestinal tract) ulceration. It works by inhibiting acid production in the stomach, so it helps to deal with situations in which the stomach produces too much acid, such as Zollinger-Ellison syndrome. Ranitidine is also prescribed for the cure of stomach diseases like gastroesophageal reflux disease (GERD) and heartburn. Ranitidine gives much more treatment efficacy than its fellow drug, Cimetidine, in the treatment of gastric diseases. Unfortunately, few brands of Ranitidine contain a cancer-inflicting impurity, N-Nitrosodimethylamine (NDMA), that becomes more harmful when the drug is stored at high temperatures. As a result, the United States Food and Drug Administration (FDA) has requested all pharmaceutical companies to withdraw Ranitidine from the market in the United States of America. Always consume Ranitidine only if the doctor prescribes it.

Drug Group:

Ranitidine is an antacid belonging to a class of H2 receptor blockers. It is a competitive inhibitor of histamine H2-receptors and acts by reversibly inhibiting H2-receptors in parietal cells of the stomach. As a result, the production of acid is stopped. Other drugs in this class are Cimetidine and Famotidine.

What Are the Uses of Ranitidine?

Ranitidine suppresses the production of the acid in the GIT. Ranitidine, with a combination of other drugs, is used as antacid therapy in numerous gastric diseases like duodenal ulcer, heartburn, Zollinger-Ellison syndrome, and associated hyperacidity, GERD symptoms, systemic mastocytosis, benign gastric ulcers, and other medical conditions that can cause acidity.

Other Uses of Ranitidine Include:

It prevents stress ulcers and stomach damage from the use of nonsteroidal anti-inflammatory drugs (NSAIDs). NSAIDs block the production of mucus layer on the stomach lining; hence the stomach becomes more susceptible to ulceration by the acid. Ranitidine protects against NSAID damage. Ranitidine is also used to treat upper gastrointestinal bleeding and aspiration of stomach acid during anesthesia and helps to relieve symptoms of cough.


The U.S. Food and Drug Administration, in the year 2020, recommended all Ranitidine manufacturers remove all the Ranitidine from the market as the drug contains highly carcinogenic substances N-Nitrosodimethylamine (NDMA). Never take Ranitidine or any other medicine without consulting your doctor first.

How Does Ranitidine Work?

Ranitidine blocks the action of the hormone gastrin on Histamine-2 receptors in the stomach lining cells and thus stops the production of acids in the stomach.

Onset of Action:

Ranitidine is rapidly absorbed and reaches peak concentrations within one to three hours after the drug is taken. Ranitidine undergoes hepatic metabolism to the bioavailability of about 50 % to 60 %. Food or antacids have limited effects on absorption. An empty stomach supports good absorption of Ranitidine. The relief of gastric acid-related symptoms can occur as soon as 60 minutes after administration of a single dose, and the effects can last from four to ten hours, providing fast and effective symptomatic relief. Ranitidine is mainly excreted in the urine and feces. In an elderly population with renal dysfunction plasma, the half-life of Ranitidine is longer and is measured as three to four hours.


Ranitidine does not possess habit-forming properties.

Expiry Date:

No drug should be taken after its expiration. Please check the packaging of the medicine as the expiry date will be printed on the back of the pack.

What Is the Dosage of Ranitidine?

Depending on the types of gastric issues, the doctor prescribes a Ranitidine dose accordingly. Ranitidine is available in the injection of 25 mg/mL, syrup at 15 mg/mL, and tablets of 75 mg, 150 mg, and 300 mg.

Dosage of Ranitidine


Do not take over-the-counter Ranitidine; FDA has banned over-the-counter Ranitidine. Please consult a doctor before taking Ranitidineor any medicine.

How to Use Ranitidine?

Take Ranitidine exactly as directed. Ranitidine is available in dosage forms as a tablet, effervescent granules, effervescent tablets, and syrup to be taken orally. The doctor usually prescribes it to take once a day at bedtime or two to four times a day. In order to prevent heartburn symptoms, it should be taken 30 to 60 minutes before eating or drinking foods. Always follow the directions that are mentioned in the prescription or the package label before using the drug. For the effervescent tablets and granules, dissolve them in a full glass to consume the drug orally.

Missed Dose:

If any dose of Ranitidine is missed, take it as soon as you remember. However, if it is almost time for the next dose, do not take a double dose to make up for a missed one; skip the missed dose and continue your regular dosing schedule.

What Are the Drug Warnings and Precautions?

Talk to your doctor if you have-

  • Kidney Disease: Ranitidine should be used cautiously in a patient with renal dysfunction, and if creatinine clearances are less than 50 ml/min, the patient’s drug dose should be reduced.

  • Liver Disease: Ranitidine is metabolized in the liver; hence should be taken with precautions in liver diseases like hepatic failure, hepatitis, liver cancer, and other liver diseases.

  • Hypersensitivity Reaction: Please discuss with your doctor if you have any allergy to the drug Ranitidine or other drugs belonging to the same class.

  • Lactation: Ranitidine is excreted into human breast milk; if you are breastfeeding, do inform your doctor before starting the drug.

  • Pregnancy: Ranitidine crosses the placental barrier, so please discuss it with your doctor before taking this medicine during pregnancy.

What Are the Side Effects of Ranitidine?

  • Central Nervous System (CNS):

    • Feeling discomfort.

    • Dizziness.

    • Insomnia.

    • Vertigo.

    • Mental confusion.

    • Agitation.

    • Hallucinations.

  • Cardiovascular:

    • Irregular heartbeat.

  • Gastrointestinal:

    • Constipation.

    • Diarrhea.

    • Nausea.

    • Vomiting.

    • Abdominal discomfort.

    • Pancreatitis.

  • Hepatic:

    • Liver failure.

  • Musculoskeletal:

    • Muscle and joint pain.

  • Hematologic:

    • Leukopenia.

    • Granulocytopenia.

    • Thrombocytopenia.

    • Agranulocytosis.

  • Endocrine:

  • Other:

    • Hypersensitivity reactions.

    • Anaphylaxis.

This is not a complete list of Ranitidine side effects. Ask your doctor or pharmacist for more information.

What Are the Interactions of Ranitidine?

Pharmacological interactions occur among different drugs and drugs with food. Please check the below-mentioned drug interactions of Ranitidine:

1. With Medicine:

Moderate interactions of Ranitidine include:

  • Alendronate.

  • Ceftibuten.

  • Cyanocobalamin.

  • Ethotoin.

  • Etravirine.

  • Fosphenytoin.

  • Hydrochlorothiazide.

  • Midodrine.

  • Miglitol.

  • Phenytoin.

  • Phytoestrogens.

Serious drug interactions of Ranitidine include:

  • Atazanavir

  • Dasatinib.

  • Delavirdine.

  • Erlotinib.

  • Itraconazole.

  • Ivacaftor.

  • Ketoconazole.

  • Mesalamine.

  • Pazopanib.

  • Ponatinib.

  • Risedronate.

2. With Alcohol - Ranitidine does not show any interaction with the alcohol.

3. With Food - No interactions are reported between food and Ranitidine; however, it shows

good absorption when taken on an empty stomach.

What Are the Common Brands or Trade Names of Ranitidine Available in the Market?

  1. Tablet Zantac 300 mg.

  2. Powder Ranitidine HCl.

  3. Tablet Zantac 25 overdose.

  4. Effervescent tablets Zantac EFFERdose 25 mg.

  5. Tablet Zantac 150 mg.

  6. Capsule Ranitidine HCl 300 mg.

  7. Vial Ranitidine HCl 25 mg/ml.

  8. Vial Zantac 25 mg/ml vial.

Frequently Asked Questions


What Are the Uses of Ranitidine?

Ranitidine has been traditionally used to treat and prevent stomach and intestine ulcers, indigestion, acid reflux, and heartburn. It also treats conditions like Zollinger-Ellison syndrome (stomach producing too much acid) and gastroesophageal reflux disease (GERD-acid flow back from the stomach into the esophagus).


Does Ranitidine Have Any Adverse Effects?

The side effects of Ranitidine are mild and temporary, which include headaches, diarrhea, constipation, abdominal pain, hair loss, dizziness, nausea, vomiting, and anemia. Rare but serious side effects include liver failure, pancreatitis, deficiency of platelets in the blood, and reduction of all blood cells.


Who Is Contraindicated for Ranitidine Intake?

Ranitidine should not be given to:
 - Children younger than age 12.
 - People with severe kidney diseases.
 - Acute porphyria patients.
 - Hypersensitivity reaction to Ranitidine.


How Long Can a Person Take Ranitidine?

Unless a healthcare professional suggests otherwise, Ranitidine is not used longer than two weeks. Ranitidine may be used for up to one year to maintain healed gastric or duodenal ulcers.


Can Kidney Damage Occur Due to Ranitidine Intake?

Prolonged use of Ranitidine can lead to serious kidney damage, even in people with no kidney problems, because it contains a chemical called N-Nitrosodimethylamine (NDMA), which can reduce kidney function and cause kidney cancer.


When Should We Take Ranitidine?

Taking Ranitidine 30 to 60 minutes before eating food or drinking beverages is recommended. It can be used up to twice every day. It reduces the stomach's acid to treat issues like heartburn and indigestion.


Is Morning or Night the Best Time to Take Ranitidine?

Ranitidine is more effective before bedtime, as it helps eliminate esophageal acid exposure and decreases overnight gastric acid secretion in patients. Stomach acid secretion usually increases at night between 10:00 PM and 2:00 AM.


What Is the Safe Dose of Ranitidine?

The standard dosage regimen of Ranitidine is 300 mg at night or 150 mg twice daily to prevent heartburn and acid indigestion. Consuming more than two tablets daily is not advisable because an overdose of Ranitidine can cause side effects like nausea, vomiting, diarrhea, and drowsiness.


How Fast Does Ranitidine Work?

Ranitidine starts working within 30 minutes of its intake and reaches its peak effect after two to three hours of taking a 150 mg dose. The active ingredient in Ranitidine blocks a chemical called histamine and reduces acid production in the stomach. 


Is Ranitidine Effective in Relieving Gas?

Ranitidine is an effective drug in relieving gas and other digestive problems. It reduces the acid production in the stomach, thereby relieving indigestion issues and associated problems.

Last reviewed at:
17 Oct 2022  -  6 min read




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