Ranitidine

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Ranitidine belongs to a group of medicines called H2 antagonists, which reduce the amount of stomach acid production . Ranitidine is commonly used in treatment of peptic ulcer disease (PUD), heartburn, ulcers caused by Non steroidal anti-inflammatory drugs (NSAIDs) and gastroesophageal reflux disease (GERD).

Contents

[edit] BRAND NAMES

[edit] STRUCTURE

Ranitidine.jpg

[edit] MECHANISM OF ACTION

Ranitidine is a competitive, reversible inhibitor of the action of histamine at the histamine H2-receptors, including receptors on the gastric cells and thus inhibits stomach acid production

[edit] INDICATIONS

  • Short-term treatment of active duodenal ulcer and maintenance therapy for duodenal ulcer patients after healing.
  • Treatment of pathological hypersecretory conditions (e.g., Zollinger-Ellison syndrome and systemic mastocytosis).
  • Short-term treatment and maintenance therapy of benign gastric ulcer.
  • Treatment of gastroesophageal reflux disease (GERD) including erosive esophagitis

Concomitant antacids should be given as needed for pain relief to patients with active duodenal ulcer; active, benign gastric ulcer; hypersecretory states; GERD; and erosive esophagitis.

[edit] DOSAGE

ORALLY:

Adults:

  • Active Duodenal Ulcer and Benign Gastric Ulcer:
    • Treatment:150 mg twice daily or 300 mg once daily after the evening meal or at bedtime.
    • Maintenance of Healing: 150 mg at bedtime.
  • Erosive Esophagitis:
    • Treatment: 150 mg 4 times daily
    • Maintenance of Healing: 150 mg twice daily
  • Gastroesophageal Reflux Disease: 150 mg twice daily


Pediatric Use:

  • Active Duodenal Ulcer and Benign Gastric Ulcer:
    • Treatment: 2 to 4 mg/kg twice daily to a maximum of 300 mg/day.
    • Maintenance of Healing: to 4 mg/kg once daily to a maximum of 150 mg/day.
  • Gastroesophageal Reflux Disease and Erosive Esophagitis: published literature supports a dosage of 5 to 10 mg/kg/day, usually given as 2 divided doses


IV FORMULATION:

The IV formulation is important for patients hospitalized in Intensive Care Unit who need to use drugs which may cause GI bleeding, mucositis and ulcers. Such patients cannot use oral formulations of ranitidine. They will rather be given ranitidine by IV. The IV formulation has a quicker onset of action and is good for acute situations, especially in Intensive Care Unit.

[edit] CONTRAINDICATIONS

  • Hypersensitivity to Ranitidine

[edit] WARNINGS AND PRECAUTIONS

  • Symptomatic response to therapy does not rule out the presence of gastric malignancy
  • Rare reports suggest that Ranitidine may precipitate acute porphyric attacks in patients with acute porphyria. Ranitidine should therefore be avoided in patients with a history of acute porphyria

[edit] INTERACTIONS

  • Warfarin: There have been reports of altered prothrombin time among patients on concomitant warfarin and ranitidine therapy. Due to the narrow therapeutic index, close monitoring of increased or decreased prothrombin time is recommended during concurrent treatment with ranitidine.
  • High doses of ranitidine (e.g., such as those used in the treatment of Zollinger-Ellison syndrome) have been shown to reduce the renal excretion of procainamide
  • Atazanavir: the plasma concentrations and therapeutic effects of this antiretroviral drug may be reduced.
  • Delavirdine: Delavirdine absorption may be impaired based on known interactions with other agents that increase gastric pH. Chronic use of H2-receptor antagonists with delavirdine is not recommended.
  • Gefitinib: Gefitinib exposure was reduced by 44% with the coadministration of ranitidine and sodium bicarbonate (dosed to maintain gastric pH above 5.0). Use with caution.
  • Glipizide: In diabetic patients, glipizide exposure was increased by 34% following a single 150 mg dose of oral ranitidine. Use appropriate clinical monitoring when initiating or discontinuing ranitidine.
  • Ketoconazole: Oral ketoconazole exposure was reduced by up to 95% when oral ranitidine was coadministered in a regimen to maintain a gastric pH of 6 or above. The degree of interaction with usual dose of ranitidine (150 mg twice daily) is unknown.
  • Midazolam: Oral midazolam exposure in 5 healthy volunteers was increased by up to 65% when administered with oral ranitidine at a dose of 150 mg twice daily. However, in another interaction study in 8 volunteers receiving IV midazolam, a 300 mg oral dose of ranitidine increased midazolam exposure by about 9%. Monitor patients for excessive or prolonged sedation when ranitidine is coadministered with oral midazolam.
  • Triazolam: Triazolam exposure in healthy volunteers was increased by approximately 30% when administered with oral ranitidine at a dose of 150 mg twice daily. Monitor patients for ecessive or prolonged sedation

[edit] PREGNANCY AND LACTATION

  • Pregnancy Category B (US). Reproduction studies have been performed in rats and rabbits at doses up to 160 times the human dose and have revealed no evidence of impaired fertility or harm to the fetus due to Ranitidine. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
  • Nursing Mothers: Ranitidine is secreted in human milk. Caution should be exercised when Ranitidine is administered to a nursing mother.

[edit] SIDE EFFECTS

Possible adverse reactions include: Headache

[edit] RELATED LINKS

[edit] BIBLIOGRAPHY

[edit] REFERENCES

Heartburn/Gastritis/Gastric ulcer/Duodenal ulcer/Gastroesophageal reflux
H2 antagonists Famotidine   Nizatidine   Ranitidine (Zantac)
Proton-pump inhibitors Dexlansoprazole (Dexilant)   Esomeprazole (Nexium)   Lansoprazole (Prevacid)   Omeprazole (Losec, Prilosec)   Omeprazole/Sodium bicarbonate (Zegerid)   Pantoprazole (Controloc, Pantecta, Pantoloc, Protonix) (  Rabeprazole (Aciphex, Pariet)
Prostaglandins Misoprostol (Cytotec)
Other drugs Alginic acid   Magaldrate   Sucralfate
Combination Regimens Bismuth Subcitrate Potassium/Metronidazole/Tetracycline (Pylera)   Lansoprazole/Amoxicillin/Clarithromycin (Prevpac)