Ranitidine Pharmacology


About Ranitidine
A histamine H2-receptor antagonist, Furan derivative, Anti-secretory G.I agent,Anti ulcer.
Mechanism of Action of Ranitidine
Ranitidine is a H2 (Histamine) receptor antagonist. Histamine is the most potent stimulus of acid secretion and acts as the common mediator. H2 receptor is a G-protein coupled receptor. It induces adenylate cyclase which converts ATP to cyclic AMP. This cyclic AMP acts on proton pump and exchange extracellular potassium ion for intracellular hydrogen ion across the parietal cell membrane. Ranitidine reversibly competes with Histamine for binding to H2 receptors on the parietal cells and predominantly inhibits basal acid secretion.
Anaesthetic adjuncts: It is used in patients undergoing prolonged operations, caesarian section,obese patients those are at increased risk of gastric regurgitation and aspiration pneumonia. It raises pH of gastric juice and also reduces its volume and thus chances of regurgitation. It is now routinely used before prolonged surgery.
Pharmacokinets of Ranitidine
Absorption: Ranitidine is 50 % absorbed after oral administration. Distribution: Distributed mainly to body tissues in unbound form. Metabolism: Ranitidine undergoes metabolism in the liver. Excretion: It is excreted mainly in urine and in the faeces.
Onset of Action for Ranitidine
60 minutes
Duration of Action for Ranitidine
Half Life of Ranitidine
1.6- 2.4 hours
Side Effects of Ranitidine
1. Headache
2. Dizziness
3. Constipation
4. Vertigo
5. Confusion
6. Rash
7. Blurred vision
8. Thrombocytopenia
9. Leukopenia
Contra-indications of Ranitidine
1. Hypersensitivity to Ranitidine
Special Precautions while taking Ranitidine
1. Hepatic impairment
2. Renal impairment
3. Acute Porphyria
Pregnancy Related Information
Use with caution
Old Age Related Information
Use with caution
Breast Feeding Related Information
Use with caution
Children Related Information
Use with caution
NEONATES: Contraindicated
Indications for Ranitidine
1. Duodenal ulcer
2. Benign gastric ulcer
3. Zollinger- Ellison syndrome
4. Gastroesophageal reflux
5. Acid indigestion
6. Heart burn
7. Sour stomach
8. Stress ulcers
9. Oesophagitis
10.Preanaesthetic medication
Interactions for Ranitidine
Antacids: Ranitidine absorption may be decreased.
Diazepam: Efficacy of diazepam decreased.
Procainamide: Renal clearance of procainamide decreased.
Sulfonylureas: Hypoglycemic effects of glipizide enhanced.
Theophyllines: Increased efficacy of theophyllines with possible toxicity.
Warfarin: Increased hypoprothrombinemic effects.
Lab tests: False positive tests for urine proteins with multistix may occur.
Typical Dosage for Ranitidine
Adult: 300mg / day
Duodenal ulcer, benign gastric ulcer: 300 mg /day as single dose at bed time or in 2 divided dose (morning and bed time) for minimum of 4 weeks.
Maintenance dose: 150 mg / day at bed time.
Zollinger- Ellison syndrome: 300 - 450 mg / day in 2 - 3 divided doses; dose can be increased if necessary to a maximum up to 6g / day .
Gastroesophageal reflux: 300 mg / day as single dose at bed time or in 2 divided doses (morning and bed time) for maximum 2 months. In severe conditions dose can be increased to 600 mg / day in 4 divided doses for 3 months
Acid indigestion, Heart burn, Sour stomach: Dose: 75 mg once daily to a maximum up to 150 mg / day.
Oesophagitis: 150 mg/ day.
Dyspepsia: 75 - 300 mg / day depending on the severity of disease.
PAM: 150mg given night and in the morning before surgical procedures.
Duodenal ulcer, benign gastric ulcer: 4 - 8 mg / kg body weight / day in 2 divided doses.
Maximum dose: 300 mg / day
Schedule of Ranitidine
Storage Requirements for Ranitidine
Store at 15 - 30 degree C in a tightly closed container. Protect from light.
Effects of Missed Dosage of Ranitidine
Take the missed dose as soon as noticed and if it is the time for next dose then skip the missed dose. Continue the regular schedule. Do not double the dose.
Effects of Overdose of Ranitidine
Give supportive measures and symptomatic treatment. Drug can be removed from the body by inducing emesis and or by gastric lavage. Activated charcoal is given to reduce the absorption of the drug. Haemodialysis can be done if necessary.

Home Delivery for Ranitidine in Your City

Medicine India is just a publishing medium for medicine related information and does not provide services or sales of medicines including ranitidine.

However, we do publish a comprehensive directory of Pharmacies, Chemists and Druggists in cities all over India. You can use this directory to find the medicine stores in your city (or area) that provide home delivery services for ranitidine and other medicines and health products. Home delivery services for ranitidine may be free or they may cost you depending on the pharmacy and the minimum order requirements. It would be best to get this clarified while placing the order.

Please be aware that you should take ranitidine only if a doctor has recommended or prescribed it. Some or all pharmacies who provide a home delivery service for medicines might insist on a prescription for ranitidine before they complete the sale. You can get this information while placing the order for ranitidine with the pharmacy.

Ranitidine is a generic medicine name and there are several brands available for it. Some of the brands for ranitidine might be better known than ranitidine itself. If the pharmacy that's willing to deliver medicines to your home doesn't have ranitidine in stock, you can ask for one of the branded alternatives for ranitidine.