Ranitidine

Indications

Ranitidine is used for: Dyspepsia, H. pylori infection, Benign gastric and duodenal ulceration, GERD, Acid aspiration during general anesth, Prophylaxis during NSAID treatment, Stress ulceration of upper GI, Zollinger-Ellison syndrome

Adult Dose

Oral Benign gastric and duodenal ulceration Adult: Initially, 300 mg daily at bedtime or 150 mg bid for 4-8 wk; 300 mg bid for 4 wk may be used in duodenal ulcer to improved healing. Maintenance: 150 mg daily at bedtime. Max: 300 mg bid. Hypersecretory conditions Adult: Initially, 150 mg bid or tid and increased if needed. Max: 6 g daily. Gastro-oesophageal reflux disease Adult: 150 mg bid or 300 mg at bedtime for up to 8 wk, may increase to 150 mg 4 times daily for 12 wk in severe cases. Dyspepsia Adult: Chronic episodic: 150 mg bid for up to 6 wk. Short-term symptomatic relief: 75 mg repeated if necessary up to 4 doses daily. Max duration: 2 wk of continuous use at one time. Erosive oesophagitis Adult: 150 mg 4 times daily. Maintenance: 150 mg bid. NSAID-associated ulceration Adult: 150 mg bid or 300 mg at bedtime for 8-12 wk. For prevention of NSAID-associated ulceration: 150 mg bid. Hepatic impairment: Dosage adjustment not necessary

Child Dose

Oral Benign gastric and duodenal ulceration Child: 1 mth to 16 yr 4-8 mg/kg daily in 2 divided doses. Max: 300 mg/day. Treatment duration: 4-8 wk. Maintenance: 2-4 mg/kg once daily. Max: 150 mg/day. Gastro-oesophageal reflux disease Child: 1 mth to 16 yr 5-10 mg/kg daily in 2 divided doses. Max: 300 mg/day. Erosive oesophagitis Child: 1 mth to 16 yr 5-10 mg/kg daily in 2 divided doses. Max: 600 mg/day.

Renal Dose

Oral: CrCl Dosage <50 150 mg daily at bedtime, adjust dose cautiously if necessary.Parenteral: Individual doses may be reduced to 25 mg.

Administration

May be taken with or without food. IV Administration Direct injection: 50 mg diluted to ?20 mL with compatible IV infusion fluid and given over ?5 minutes (4 mL/min) Intermittent infusion: 50 mg added to ?100 mL of compatible IV solution and infused over 15-20 minutes Continuous infusion: 150 mg diluted in 250 mL of IV fluid and infused at 6.25 mg/hr for 24 hours

Contra Indications

Porphyria.

Precautions

Possibility of malignancy should be excluded prior to therapy as the drug may mask symptoms and delay diagnosis of gastric malignancy. Patients w/ difficulty in swallowing. Renal and hepatic impairment. Pregnancy and lactation. Lactation: Drug crosses into breast milk; discontinue drug, use caution

Pregnancy-Lactation

Interactions

Delayed absorption and increased peak serum concentration w/ propantheline bromide. Ranitidine minimally inhibits hepatic metabolism of coumarin anticoagulants, theophylline, diazepam and propanolol. May alter absorption of pH-dependent drugs (e.g. ketoconazole, midazolam, glipizide). May reduce bioavailability w/ antacids.

Adverse Effects

Side effects of Ranitidine : 1-10% Headache (3%) <1% Abdominal pain,Agitation,Alopecia,Confusion,Constipation,Diarrhea,Dizziness,Hypersensitivity reaction,Nausea,Vomiting Frequency Not Defined Anemia,Necrotizing enterocolitis in fetus or newborn,Pancreatitis (rare),Thrombocytopenia (rare),Pancytopenia (rare),Agranulocytosis (rare),Acquired immune hemolytic anemia (rare),Arthralgia (rare),Myalgia (rare) Potentially Fatal: Anaphylaxis, hypersensitivity reactions.

Mechanism of Action

Ranitidine competitively blocks histamine at H2-receptors of the gastric parietal cells which inhibits gastric acid secretion. It does not affect pepsin secretion, pentagastrin-stimulated intrinsic factor secretion or serum gastrin.