Ranitidine Uses and Precautions


Ranitidine is a non-imidazole blocker of histamine receptors which is used for the treatment of gastrointestinal ulcers. Ranitidine is grouped as histamine (H2)-receptor antagonist class of drugs. Get to know how Ranitidine works, its side effects, precautions, and contraindications where Ranitidine is not suggested.

How does the drug work?

These drugs inhibit the action of histamine on parietal cells of the stomach, and hence reduces acid secretion.

1. Few Important facts about Ranitidine
2. Indications
3. Mechanism of Action
4. Ranitidine Brand Names in the US
5. Interactions
6. Drug Interactions of Ranitidine
7. Precautions before using Ranitidine
8. Mutagenecity and Teratogenecity
9. Pediatrics
10. Adverse Drug Reactions
11. Ranitidine Dosage
12. Drug Overdose
13. Toxicity

Few Important facts about Ranitidine

The maximum allowed dose of ranitidine is 400 mg/day. The bioavailability of ranitidine is approximately 50% when taken orally; the drug has a half-life of 2.8 to 3.1 hours.

The half-life of a drug refers to the duration of time required for the concentration of the drug to deplete to half its maximum concentration reached in the body.

This drug is metabolized in the liver and is primarily excreted through urine. Meanwhile, 30% of the orally consumed drug is expelled unchanged through kidneys within 24 hours.

Ranitidine is used for treating:

  • Peptic ulcer disease (PUD)
  • Dyspepsia
  • Gastroesophageal reflux disease (GERD).
  • Erosive Esophagitis(EE)
  • Gastroesophageal Reflux Disease
  • Heartburn
  • Peptic Ulcer Disease
  • Stress Ulcers
  • Systemic Mastocytosis
  • Zollinger-Ellison Syndrome
  • Benign gastric ulcers

Besides, this drug has been also found to be efficacious for the prophylaxis of stress ulcers.

Mechanism of Action

Ranitidine suppresses or inhibits acid secretion by parietal cells, especially after meals. Therefore, this drug is beneficial for prevention of gastric symptoms associated with increased acid production or ‘acidity’.

Ranitidine Brand Names in the US

Ranitidine is commonly available in the United States under the following trade names:

  • Ranitidine Actavis
  • Zantac
Read more about Indian version of Ranitidine: Rantac 150mg Tablet


Ranitidine is known for certain foods and beverages. Therefore, it is essential to avoid them while on this drug regime

  • Alcohol
  • Excess intake of tea or coffee
  • Milk and calcium-containing dairy products
  • Foods having high iron content

Ideally, ranitidine should be taken before meals for optimal benefit, since the drug interacts with most foods.

Drug Interactions of Ranitidine

Ranitidine is known to interact with the following drugs:

  • Antacids and drugs containing aluminum salts
  • Warfarin
  • 2,5-Dimethoxy-4-ethylamphetamine
  • 3,4-Methylenedioxyamphetamine
  • 4-Bromo-2,5-dimethoxyamphetamine
  • Abiraterone
  • Acebutolol
  • Acetaminophen
  • Acetaminophen
  • Acetohexamide
  • Acetohexamide
  • Acetylsalicylic acid
  • Afatinib
  • Albendazole

Precautions before using Ranitidine

Ranitidine dosage should be adjusted in patients with:

  • Impaired renal function and in geriatric patients.
  • In patients with hepatic dysfunction.
  • Should be avoided in patients with a history of acute porphyria.

Mutagenecity and Teratogenecity

Although ranitidine is not proven to have mutagenic or teratogenic effects, yet it has been recommended for use during pregnancy only if its benefits justify the risks.

However, the drug is excreted in human milk, thus, is contraindicated for use in lactating women.


This is found to be safe for use in neonates and pediatric patients belonging to the age group of 1 month to 16 years.

Adverse Drug Reactions

A few adverse effects, although mild, have been reported with ranitidine; they are:

  • Headache
  • Malaise
  • Dizziness
  • Somnolence
  • Insomnia
  • Vertigo
  • Arrhythmias
  • Constipation/diarrhea
  • Nausea/vomiting
  • Abdominal discomfort/pain
  • Athralgia
  • Myalgia

Rarely, hepatocellular, cholestatic, or mixed hepatitis have been reported with this drug. In such cases, the drug must be stopped immediately and medical help should be sought.

Ranitidine Dosage

Below we enlist the doses of ranitidine based on its various indications:

  • Duodenal Ulcer Adult – 150 mg or 10 mL of syrup, twice daily; alternatively 300 mg or 20 mL of syrup, once daily.
  • Inhibition of gastric acid secretion – 100 mg twice daily
  • Maintenance of Healing of Duodenal Ulcers – 150 mg or 10 mL of syrup, at bedtime.
  • Zollinger-Ellison syndrome – 150 mg or 10 mL of syrup, twice daily.
  • Benign Gastric Ulcer – 150 mg or 10 mL of syrup, twice daily.
  • Maintenance of Healing of Gastric Ulcers -150 mg or 10 mL of syrup, twice daily.
  • GERD – 150 mg or 10 mL of syrup, twice daily.
  • Erosive Esophagitis – 150 mg or 10 mL of syrup, four times daily.
  • Maintenance of Healing of Erosive Esophagitis – 150 mg or 10 mL of syrup, twice daily.
  • Severe gastrointestinal diseases – up to 6 g daily.

Dosage and duration of treatment must be adjusted based on individual needs and clinical indication.

Drug Overdose

In case of overdosage of ranitidine usual measures, vis extraction of unabsorbed material from the gastrointestinal tract, clinical monitoring, and supportive therapy are helpful.

Adverse effects of ranitidine overdose include altered gait and hypotension


Symptoms of drug toxicity include muscular tremors, vomiting, and rapid respiration.

Ranitidine has been found to be safe for use in pediatric patients in the age-group of 1 month to 16 years of age, as well as in geriatric patients. However, dose adjustment is necessary for patients with impaired renal function.

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