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Drug dosage identifier


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Dose and administration

  1. Intravenous (slow infusion over 15 minutes)
    1. Preterm infants <32 weeks and <7 days: 0.5mg/kg every 12 hours
    2. Term infants: 0.5mg/kg every 8 hours
  2. Oral: 2mg/kg every 8 hours


Safety and efficacy in children has not been established in clinical trials.

  1. Treatment of acute gastrointestinal bleeding or stress ulcers.

Contraindications and precautions

  1. Known hypersensitivity to ranitidine.
  2. Caution in neonates with renal impairment (see "Special Considerations").
  3. Possible necrotising enterocolitis (see "Special Considerations").

Clinical pharmacology

Ranitidine is a highly effective, rapidly acting histamine H2 receptor antagonist. It inhibits both basal stimulated gastric secretions (volume, acid and pepsin content reduced).

Peak plasma concentration occurs 15 minutes after an IV dose and 1-3 hours after an oral dose (in adults). Oral administration is not influenced by food. Ranitidine is not extensively metabolised; elimination is predominantly renal with 70% of an IV dose and 35-70% of an oral dose eliminated unchanged. Normal elimination half-life in children is 2-3 hours but is prolonged in patients with renal insufficiency. Very limited data available describing pharmacokinetics and pharmacodynamics in the newborn.

Possible adverse effects

  1. Rarely, bradycardia or arrhythmias if administration is too rapid.
  2. Hepatitis with or without jaundice (rare, and usually reversible).
  3. Diarrhoea (rarely)
  4. Skin rash.

Drug interactions

  1. Antacids: separate antacid and oral ranitidine doses by an hour.
  2. Phenytoin: monitor for signs of phenytoin toxicity.

Special considerations

  1. Severe renal impairment: use half the normal dose
  2. Ranitidine has been associated with necrotising enterocolitis. Whilst this may be because infants with early symptoms of NEC might be treated with ranitidine before the diagnosis is apparent, randitine may potentially contribute to NEC by reducing gastric pH.11

Management of Ranitidine administration


IV preparation
Clear, colourless to yellow solution 25 mg/ml in 2 ml ampoules.
Preparation includes sodium chloride, potassium dihydrogen phosphate and disodium hydrogen phosphate.
pH 6.7-7.3, with an osmolality of 257 mOsmol/kg in 5% glucose and 294 mOsmolkg in 0.9% NaCl.
Oral preparation
Sugar free syrup 15 mg/ml.
Additives include ethanol (7.5% w/v), methylcellulose, hydroxybenzoates, potassium dihydrogen phosphate, disodium hydrogen phosphate, sodium chloride, saccharin sodium, sorbitol, and mint flavour.


Charted on prescription chart in mg/dose.


Slow IV Infusion
Dilute immediately prior to use to 1 mg/ml by adding. The suggested / recommended way of obtaining the correct dilution is that 0.2 ml (5mg) be added to 4.8ml normal saline making 5mg/5ml (thus 1mg/ml).
Can be diluted to 2mg/ml in fluid-restricted babies.
Compatible with 0.9% NaCl, 5% glucose, or 10% glucose
Filter prior to administration through a Pall 0.2 micron filter. May be filtered through a 0.2 micron filter.
Administer by slow IV infusion over 15 minutes using a syringe pump.
Compatible at the Y-site with dobutamine, dopamine, fluconazole and morphine when diluted to concentrations used in the Newborn Services protocols.
Do NOT mix with blood or blood products.
Incompatible with insulin.
Flush line with 0.9% NaCl before and after infusion of ranitidine.
Oral ranitidine may be given without regard to timing of feeds.
Administer antacids one hour before or two hours after ranitidine.

Observation and documentation

  1. Monitor for signs of adverse effects.
  2. If bradycardia or arrhythmias occur during administration, discontinue the infusion and notify medical staff.
  3. Observe for signs of hepatic and renal dysfunction.


IV preparation
<25°C. Protect from light.


Selected references

  1. Northern Neonatal Network. Neonatal Formulary 4. London: BMJ Books,2003
  2. Kuusela AL. Long-term gastric pH monitoring for determining optimal dose of ranitidine for critically ill preterm and term neonates. Arch Dis Child Fetal Neonatal Ed 1998;78(2):F151-3.
  3. Neonatal Formulary: Drug use in pregnancy and the first year of life (5th ed). Blackwell Publishing, 2007.
  4. Zantac (Ranitidine) Data sheet .Auckland: GlaxoSmithKline NZ limited,2005.
  5. Medicines for Children. Royal College of Paediatrics and Child Health. London: RCPCH Publications Limited, 2003.
  6. Baxter K (ed). Stockley's Drug Interactions (7th ed.) London: Pharmaceutical Press:2006
  7. Mehta DK (ed). BNF for children.London:BMJ Publishing Group Ltd,2006
  8. Trissell LA (ed.). Handbook of Injectable Drugs (14th ed.). Bethesda; American Society of Health System Pharmacists:2007.
  9. Fary R, SmithR(eds.). RWH Neonatal Pharmacopoeia(2nd ed). Melbourne: Pharmacy Department, The Royal Women's Hospital,2005
  10. Sutphen JL, Dillard VL. Effect of ranitidine on twenty-four hour gastric acidity in infants. J Pediatrics 1989; March: 472-474.
  11. Guillet R, Stoll BJ, Cotten, M, et al. Association of H2-blocker therapy and higher incidence of necrotizing enterocolitis in very low birth weight infants. Pediatrics 2006;117(2):e137-42.

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Document Control

  • Date last published: 30 August 2007
  • Document type: Drug Dosage Guideline
  • Services responsible: Neonatology, ADHB Pharmacy
  • Editor: Sarah Bellhouse
  • Review frequency: 2 years