Ranitidine is a histamine H2-receptor antagonist that effectively reduces stomach acid production, providing symptomatic relief and therapeutic management for a range of acid-related gastrointestinal disorders. As a well-established medication with a robust clinical history, it offers a reliable option for both short-term symptom control and longer-term maintenance therapy in appropriate patient populations. Its mechanism of action selectively inhibits histamine stimulation of parietal cells, leading to a significant decrease in basal and nocturnal gastric acid secretion without substantially affecting pepsin secretion, gastric emptying, or lower esophageal sphincter pressure.

Features

• Selective histamine H2-receptor antagonist
• Available in multiple formulations: tablets, effervescent tablets, syrup, and injectable solutions
• Rapid onset of action with effects typically beginning within 1-3 hours after oral administration
• Duration of acid suppression lasting 4-12 hours depending on dosage
• Demonstrated efficacy in reducing both basal and stimulated gastric acid secretion
• Well-characterized pharmacokinetic profile with predictable absorption and elimination

Benefits

• Provides rapid relief from heartburn, acid indigestion, and sour stomach
• Effectively promotes healing of gastric and duodenal ulcers
• Reduces symptoms of gastroesophageal reflux disease (GERD)
• Prevents acid-related damage to esophageal mucosa
• Decreases gastric acid volume and concentration
• Offers flexible dosing regimens for both acute and maintenance therapy

Common use

Ranitidine is clinically indicated for the short-term treatment of active duodenal ulcers and benign gastric ulcers. It is also prescribed for maintenance therapy after healing of duodenal ulcers to prevent recurrence. The medication is effective in treating pathological hypersecretory conditions such as Zollinger-Ellison syndrome and systemic mastocytosis. Additionally, it is commonly used for the treatment of gastroesophageal reflux disease (GERD), including erosive esophagitis, and for the relief of heartburn and acid indigestion. Some clinicians may recommend ranitidine for stress ulcer prophylaxis in hospitalized patients, though practice patterns vary based on current guidelines and institutional protocols.

Dosage and direction

For active duodenal ulcer treatment: 150 mg twice daily or 300 mg once daily at bedtime for 4-8 weeks. Maintenance therapy for duodenal ulcer: 150 mg at bedtime. For gastric ulcers: 150 mg twice daily. GERD treatment: 150 mg twice daily. Pathological hypersecretory conditions: 150 mg twice daily, adjustable up to 6 g daily in divided doses based on patient response. For heartburn and acid indigestion: 75-150 mg as needed, not to exceed 300 mg in 24 hours. Tablets should be swallowed whole with water; effervescent tablets must be completely dissolved in water before consumption. Administration timing may be adjusted based on symptom patterns, with bedtime dosing particularly effective for nocturnal acid breakthrough.

Precautions

Patients with hepatic impairment require dosage adjustment and careful monitoring due to reduced metabolism. Renal impairment necessitates modified dosing schedules as ranitidine is primarily eliminated renally. Use with caution in patients with porphyria as ranitidine may precipitate acute attacks. Long-term therapy may lead to vitamin B12 deficiency due to impaired absorption; periodic monitoring may be warranted. abrupt discontinuation after prolonged use may result in rebound acid hypersecretion. Patients should be advised that ranitidine may mask symptoms of gastric malignancy, thus proper diagnostic evaluation should precede treatment initiation. Regular monitoring of gastric pH may be necessary in critically ill patients receiving stress ulcer prophylaxis.

Contraindications

Ranitidine is contraindicated in patients with known hypersensitivity to ranitidine or any component of the formulation. It should not be used in patients with acute porphyria or history of acute porphyric attacks. Contraindicated in patients with demonstrated cross-sensitivity to other H2-receptor antagonists. Not recommended for patients with phenylketonuria when using formulations containing aspartame. Use is contraindicated in patients with severe renal impairment without appropriate dosage adjustment and monitoring.

Possible side effect

Common adverse effects include headache, constipation, diarrhea, nausea, vomiting, and abdominal discomfort. Less frequently reported effects include dizziness, somnolence, insomnia, vertigo, and reversible mental confusion particularly in elderly or severely ill patients. Rare but serious side effects may include hepatitis, hepatocellular or mixed hepatocellular-cholestatic injury, pancreatitis, blood dyscrasias (thrombocytopenia, leukopenia, granulocytopenia, pancytopenia), and cardiovascular effects (bradycardia, tachycardia, atrioventricular block). Hypersensitivity reactions including bronchospasm, fever, rash, eosinophilia, and anaphylaxis have been reported. Some patients may experience arthralgia, myalgia, or loss of libido.

Drug interaction

Ranitidine may alter the absorption of drugs requiring acidic gastric environment, including ketoconazole, itraconazole, and atazanavir—separate administration by at least 2 hours. May increase serum levels of warfarin, phenytoin, procainamide, and nifedipine through potential metabolic interactions. Concomitant use with antacids may decrease ranitidine absorption; separate administration by at least 1 hour. May potentiate effects of alcohol on gastric mucosa. Interaction with high-dose aspirin may increase risk of gastric irritation. Caution with drugs that prolong QT interval due to potential additive effects. May affect bioavailability of cyanocobalamin supplements.

Missed dose

If a dose is missed, it should be taken as soon as remembered unless it is nearly time for the next scheduled dose. In that case, the missed dose should be skipped and the regular dosing schedule resumed. Patients should not double the dose to make up for a missed administration. For twice-daily regimens, if remembered within 4 hours of the next dose, skip the missed dose. For once-daily regimens, if remembered within 8 hours of the next dose, skip the missed dose. Consistency in dosing is important for optimal therapeutic effect, particularly in ulcer treatment regimens.

Overdose

Symptoms of overdose may include exaggerated pharmacological effects such as bradycardia, hypotension, and central nervous system effects including confusion, agitation, and seizures. Laboratory abnormalities may include elevated liver enzymes and electrolyte disturbances. Gastric lavage may be beneficial if performed soon after ingestion. Supportive care including monitoring of vital signs and cardiac function is essential. Hemodialysis may be effective in removing ranitidine from circulation, with clearance rates approximately 70% of creatinine clearance. There is no specific antidote; treatment should focus on symptomatic management and supportive measures.

Storage

Store at controlled room temperature between 15-30°C (59-86°F). Protect from light and moisture. Keep container tightly closed. Do not remove desiccant from packaging if present. Tablets should be kept in their original packaging until use. Oral solution should not be frozen. Keep out of reach of children and pets. Do not use after expiration date printed on packaging. Do not transfer tablets to other containers as this may affect stability. Protect effervescent tablets from humidity to prevent premature dissolution.

Disclaimer

This information is provided for educational purposes only and does not constitute medical advice. Ranitidine is a prescription medication in many jurisdictions and should be used only under the supervision of a qualified healthcare professional. Dosage and treatment duration should be determined by a physician based on individual patient assessment. Patients should not self-diagnose or self-medicate with ranitidine without proper medical evaluation. In 2020, the FDA requested removal of all ranitidine products from the market due to concerns about NDMA impurity; consult current regulatory status before use. Always follow the prescribing information provided with the medication and discuss any concerns with your healthcare provider.

Reviews

Clinical studies have demonstrated ranitidine’s efficacy with healing rates of 70-90% for duodenal ulcers at 4 weeks and significant symptom improvement in GERD patients. Many gastroenterologists consider it a well-tolerated option with a favorable risk-benefit profile in appropriate patient populations. Some clinicians note its reliable efficacy for nocturnal acid suppression despite the development of more potent acid suppressants. Patient reports frequently mention effective symptom relief, particularly for nighttime heartburn, though some note decreased effectiveness over time with chronic use. The medication generally receives positive assessments for its tolerability and predictable effect profile, though recent safety concerns have altered prescribing patterns in some regions.