RANITIDINE

General Information

 Preparation Strength

 Inj. Ranitidine Hcl 50 mg/2 ml

 Tab. Ranitidine 150 mg

Description of Drug

* It is a histamine H2 receptor antagonist.

Mode of Action

It competitively blocks the H2 receptor and thereby blocks histamine induced gastric acid secretion and reduces pepsin output.Both basal secretion and acid secretion is stimulated by food and other stimuli.

Pharmacokinetics

* Absorbed from GIT but has 50% bioavailability due to first pass metabolism. Rapidly absorbed following IM injection with in 15 minutes and bioavailability is 90%. Duration of action is 24 hours. Following IM/IV administration, clearence is rapid 6 to 8 hours.Excretion is mainly as unchanged drug in the urine.

Clinical Information

Indications

* Acid peptic disease; - gastric/duodenal ulcers both active management and in maintenance therapy.

* Zollinger - Ellison syndrome

* Gastro esophageal reflux disease, erosive esophagitis.

Dosage

Oral:

Duodenal and gastric ulcer:

Single daily dose of 300 mg by mouth at bed time or 150 mg twice daily, initially for atleast 8 weeks. - Maintenance therapy after 8 weeks 150 mg daily at bed time.

Reflux Oesophagitis and Zollinger - Ellison Syndrome: 150 mg bd for 8 weeks.

Parentral:

50 mg IM or IV every 6-8 hours.

Routes of Administration

* Oral

* Intramuscular

* Intravenous

Contraindications

* Known hypersensitivity.

Precaution / Practice Points

* Dosage to be reduced in patients with impaired renal function, when creatinine clearence is less than 50 ml/min - 150mg/day.

* IV injections should be given slowly over not less than 2 minutes and should be diluted to contain 50 mg in 20 ml.

* May precipitate attacks of porphyria.

Adverse Effects

* Headache, dizziness, diarhoea/constipation, rashes.

Rare:

* Hepatic injury, CNS and haematological changes.

* In bolus IV injection - bradycardia, arrhythmias, cardiac arrest may occur if given too rapidly.

Drug Toxicity

* CNS symptoms like malaise, headache, dizziness may occur.Disturbamce of gait/hypotension has been reported. Hepatic injury may occur.

Treatment of Toxicity

* Gastric lavage or emesis induction within 4 hours of ingestion of drug, followed by supportive and symptomatic management.

Storage

Keep in cool dark place

Shelf Life

2 years.