Letters to the Editor

Abstract

24 July 2006 Dear Editor, EXCESSIVELY HIGH DOSES OF OMEPRAZOLE BEING USED IN INFANTS I would like to raise a case history that illustrates an increasing trend of prescribing supra-therapeutic doses of Omeprazole to infants. A 6-month girl presented for assessment of poor sleeping. At 6 weeks of age, she had been an irritable infant and was prescribed Omeprazole with a presumptive diagnosis of ‘silent reflux’, by a paediatrician. She initially started 5 mg daily. This was increased to 10 mg daily and subsequently to 10 mg twice daily at 3 months of age because of a lack of effect. Her parents had felt that the dose of 10 mg twice daily had reduced her vomiting and helped her generally over the course of 4 weeks. She had continued the dose of 10 mg twice daily. At her presentation, her weight was 6.6 kg and therefore the dose was 3 mg/kg/day. One could assume that at 3 months of age the dose had been significantly higher on a per kg basis. Her parents were advised that the dose of Omeprazole was excessive and that 5 mg twice daily (1.5 mg/kg/day) was a more reasonable dosage, but they were reluctant to change the dose. The Melbourne Paediatric Drug Doses Handbook (12th Edition, Frank Shann) recommends a routine dose for Omeprazole to be 0.4–0.8 mg/kg once to twice a day. If a child has Zollinger Ellison Syndrome, then the recommended dose is 1 mg/kg once to twice a day to a maximal dose of 3 mg/kg/day.1 The MIMS annual recommends Omeprazole to be used in children >12 months of age, and reports no pharmacokinetic information in children <12 months of age.2 There is limited evidence of the use of proton pump inhibitors in infants.3 There have been case reports in adults of acute overdosage, showing little adverse effect,2, 4 but there is little information in adults or children being given supra-therapeutic doses for long periods and whether this causes more problems. Population-based adult data in England have shown relatively common side-effects, such as abdominal pain, diarrhoea, vomiting and headache.5 Rarely, hepatitis and interstitial nephritis have been associated with the use of Omeprazole.6 The off-label use of Omeprazole in infants <12 months of age is common. A frequent scenario is a 6-week infant being treated for infant irritability, diagnosed as gastro-oesophageal reflux. This is despite increasing evidence showing that there is little association between infant irritability and gastro-oesophageal reflux.7, 8 Indeed, when irritable infants with gastro-oesophageal reflux are treated with Omeprazole, there is no added clinical effect when compared with placebo.9 Infant irritability is a concerning symptom, for which parents bring their children for medical attention. It remains tempting to ‘medicalise’ the problem, as other options, such as behavioural management, can be time-consuming. As there is a natural improvement of infant irritability over time, any treatment in this age group can appear to help. It is my opinion that infants should not be given ongoing acid suppression therapy for the management of infant irritability, particularly if no benefit is gained. The practice of giving ‘supra-therapeutic doses’ of Omeprazole is concerning. There is a need to gain pharmacokinetic data in children <12 months of age. I would also encourage clinicians to report any adverse effects from treatment with Omeprazole.