RANITIDINE (Zantac): What is used for?

What is Ranitidine?

Ranitidine (Ranitidina) is a drug used to treat duodenal ulcer, peptic ulcer, Zollinger-Ellison syndrome, etc. The product ingredients are: Ranitidine hydrochloride (hcl), Ranitidine bismuth citrate.

The brand names of Ranitidine in United States are: Zantac, Zantac 150, Zantac 300, Zantac 75.

Mechanism of action (MOA) of Ranitidine

It antagonizes histamine H2 receptors in the parietal cells of the stomach. Inhibits the stimulated and basal secretion of gastric acid and reduces pepsin production.

Therapeutic Indications, Uses and Benefits of Ranitidine

In adults: duodenal ulcer; benign gastric ulcer; Zollinger-Ellison syndrome; prophylaxis of recurrent bleeding in patients with bleeding ulcer; peptic esophagitis and treatment of associated symptoms.
Prophylaxis of gastrointestinal haemorrhage due to stress ulcers in critically ill patients; preoperatively, in patients at risk of acid aspiration syndrome (Mendelson syndrome), especially obstetric patients during childbirth.

In children: short-term treatment of peptic ulcer and treatment of gastro-oesophageal reflux, including reflux esophagitis and symptomatic relief of gastro-oesophageal reflux.

Ranitidine Dosage

Adults and teenagers > 12 years

Active duodenal ulcer: oral, 150 mg 2 times/day or 300 mg nightly, 4-6 weeks. Maintenance for recurrence prophylaxis: oral, 150 mg nightly.

Benign active gastric ulcer: oral, 150 mg 2 times/day or 300 mg/24 h in the evening, 6 weeks.

S. Zollinger-Ellison: oral, initial 150 mg 3 times/day; may be increased if necessary; max. 6 g/day.

Prophylaxis of recurrent bleeding in patients with bleeding ulcer. Prophylaxis of gastrointestinal bleeding due to stress ulcer in critically ill patients: oral, 150 mg 2 times/day or 50 mg IV slow followed by continuous intravenous infusion of 0.125 or 0.250 mg/kg/h (the infus. Intravenous ranitidine is administered at a rate of 25 mg/h for 2 h which may be repeated every 6-8 h). Alternative: 50 mg/6-8 h intramuscular. IV administration should be replaced by oral administration as soon as the patient’s condition permits.

Reflux esophagitis, oral: 150 mg 2 times/day or 300 mg nightly, 6-8 weeks (or 12 weeks if necessary). If it is moderate/severe, it can be increased to 150 mg 4 times/day, up to 12 weeks. Treatment associated symptoms: 150 mg 2 times/day, 2 weeks (up to 4 weeks if initial response is not adequate).

Prevention of Mendelson’s syndrome: oral, 150 mg 2 h before general anaesthesia, and preferably another 150 mg the evening before. Alternative intramuscular or slow intravenous (min. 2 min): 50 mg 45-60 min before anaesthesia. Obstetrical patients: oral, 150 mg at the beginning of labour, followed by 150 mg/6 h.


– 3-11 years with body weight> 30 kg, oral: acute treatment of peptic ulcer, 4-8 mg/kg/day in 2 doses, 4-8 weeks; max. 300 mg/day. Gastroesophageal reflux: 5-10 mg/kg/day in 2 doses; max. 600 mg/day.

– 6 months-11 years old, acute treatment of peptic ulcer and gastroesophageal reflux, slow intravenous (min. 2 min.), max. 50 mg/6-8 h.
Renal insufficiency (Clcr < 50 ml/min): oral, 150 mg/day; IV, 25 mg.

Mode of administration of Ranitidine

Oral use. The tablets must be taken whole with water and must not be broken or crushed.

Contraindications of Ranitidine

Hypersensitivity; acute porphyria.

Warnings and Precautions with Ranitidine

Kidney failure; ruling out malignant lesions; in the elderly, with chronic lung disease, diabetes, or immunocompromised may increase the risk of developing community-acquired pneumonia; children, evaluate convenience, newborns, safety, and unestablished efficacy.
Intravenous: do not exceed speed of administration due to risk of heart rhythm disturbance.

Liver failure

Caution. Intravenous administration for more than 5 days may increase liver enzymes.

Kidney failure

Caution, adjust dose. Clcr < 50 ml/min: oral, 150 mg/day; IV, 25 mg.

Interactions with Ranitidine

  • Decreases absorption of: ketoconazole (give ranitidine min. 2 h before), atazanavir, delavirdine, gefitinib.
  • Increases absorption of: triazolam, midazolam, glipizide.
  • Decreased absorption by: highly neutralizing antacids administered on an empty stomach, such as Al or Mg hydroxides, spacing 1 h; sucralfate at high doses (administer 2 h after ranitidine).
  • Modify prothrombin time with: cumarin anticoagulants (warfarin), monitor.
  • At high doses reduces excretion of: procainamide, N-acetylprocainamide.
  • Lab: interferes with gastric acid secretion test and with skin tests with allergen extracts, do not take 24 h before.
  • False + urine protein test with Multistix (perform with sulfosalicylic acid).

Pregnancy and Ranitidine

It crosses the placental barrier. Experimental teratogenesis studies do not allow suspicion of malformations in humans, use only if considered essential. Avoid in first trimester.


Ranitidine is excreted in breast milk. It is recommended to avoid administration during lactation, unless in the opinion of the doctor is deemed essential.

Effects on driving ability

Although no such effects are to be expected, if dizziness occurs, do not drive or use dangerous machinery.

Adverse reactions and side effects of Ranitidine

Infrequent: abdominal pain, constipation, nausea (these symptoms usually improve with continued cough).


Source: The content of this active ingredient has been written taking into account the clinical and molecular information of all medicines authorised and marketed in the United States under the Unique Ingredient Identifier (UNII) by the Substance Registration System (SRS) of the Food and Drug Administration (FDA) and the United States Pharmacopeia (USP).

In order to know in detail the information authorized by the FDA for each drug, you should consult the corresponding medication guide authorized by the FDA.


UNII: 884KT10YB7
PubChem CID: 5039
NCI Thesaurus: C29412

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