Open Access Highly Accessed Study protocol

A double blind, randomised placebo controlled trial of topical 2% viscous lidocaine in improving oral intake in children with painful infectious mouth conditions

Sandy M Hopper12*, Franz E Babl123, Michelle McCarthy12, Chasari Tancharoen13, Katherine J Lee2 and Ed Oakley245

Author Affiliations

1 Department of Emergency Medicine Royal Children's Hospital, Flemington Rd, Parkville, Victoria 3052, Australia

2 Murdoch Children's Research Institute Flemington Rd Parkville Victoria 3052 Australia

3 Department of Paediatrics, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Victoria 3010 Australia

4 Southern Clinical School, Faculty of Medicine, Nursing and Health Sciences, Monash University, Victoria 3800 Australia

5 Department of Emergency Medicine Monash Medical Centre, Clayton Rd, Clayton Victoria 3168 Australia

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BMC Pediatrics 2011, 11:106  doi:10.1186/1471-2431-11-106

Published: 21 November 2011



Painful infectious mouth conditions are a common presentation to emergency departments. Although self limiting, painful ulcerative lesions and inflamed mucosa can decrease oral intake and can lead to dehydration. Oral analgesia is of limited efficacy and is often refused by the patient. Despite widespread use of oral 2% viscous lidocaine for many years, there is little evidence for its efficacy as an analgesic and in aiding oral intake in children with painful infectious mouth conditions. This study aims to establish the effectiveness of 2% viscous lidocaine in increasing oral intake in these children by comparing it with placebo.


This study is a randomised double-blind placebo controlled trial of children between 6 months and 8 years of age with painful infectious mouth conditions defined as gingivostomatitis (herpetic or non herpetic), ulcerative pharyngitis, herpangina and hand foot and mouth disease as assessed by the treating clinician in association with a history of poor oral fluid intake. It will be conducted at a single tertiary paediatric emergency department in Melbourne Australia.

20 patients have already been randomised to receive 2% lidocaine or placebo in a pilot study to determine the sample size in a preplanned adaptive design. A further 80 patients will be randomised to receive either 2% lidocaine or placebo. The placebo agent is identical to lidocaine in terms of appearance, flavour and smell. All clinical and research staff involved, patients and their parents will be blinded to treatment allocation.

The primary endpoint is the amount of fluid ingested by each child, expressed in ml/kg, within 60 minutes from the time of administration of the study mixture. Secondary endpoints are the proportion of patients ingesting 5 ml/kg and 10 ml/kg at 30 and 60 minutes after drug administration and the incidence of adverse events. Longer term outcomes will include the proportion of patients requiring hospital admission and length of emergency department stay.


This trial will define the role of 2% lidocaine in the treatment of painful infectious mouth conditions

Trial registration

The trial is registered with the Australian and New Zealand Clinical Trials Registry - ACTRN12609000566235.