Conclusion: Conflicting evidence found to make an evidence statement
Bittering agents have been proposed as a possible product modification to add to poisonous household liquids, which would help to prevent accidental poisoning in children. Bittering agents are harmless agents that make household liquids taste unpleasant and bitter and are unpalatable. It is suggested that this would deter children from ingesting the poisonous substance (Harborview Best Practices for poisoning prevention: http://depts.washington.edu/hiprc/practices/topic/poisoning/bitter.html). The bittering agent Denatonium benzoate (Bitrex), has been tested because it is non-toxic, chemically stable, and the most bitter substance known.
Klein-Schwartz et al. (1991)'s narrative review found three studies reporting the efficacy of using bittering agents. These studies (Challop, 1976; Bering et al., 1982; Sibert et al., 1988) have shown that in a controlled environment, addition of denatonium benzoate to a liquid will decrease the volume ingested. However, the number of studies are small, and these studies involved single-test situations wherein the liquid was available to the child for a limited period of time.
Kendrick et al. (2008)'s systematic review found no studies reporting outcomes on the safe use of bittering agents between 1998 and 2005. One study published since this review, by White et al 2009, examined the effectiveness of bittering agents in preventing childhood poisoning in the real world, in a comparison of states in the USA. This concluded that the addition of bittering agents to household products cannot be justified based on actual poisoning data.
Recommendations (for research & practice)
Suggestions for further research:
There is a need for a large randomized controlled trial of bittering agents. There would be concerns relating to those children who are not deterred by the bitter taste. The small scale study of Sibert et al. (1988) included in te narrative review of Klein-Schwartz et al. (1991), found one child undeterred by the unpalatable taste.
Suggestions for practice and policy:
The addition of bittering agents to household products cannot be justified based on actual poisoning data (White et al 2009).
Review Date: 18/03/2010
Articles (reviews) and reports were included that were published between 1990 and 2010, in English and Dutch. The outcomes of the study were reviewed by the Dutch Consumer Safety Institute.
Strategy: An online literature search was performed by a researcher of the Consumer Safety Institute and after this a more thorough search was performed by the documentation centre of CSI (Catalog CenV, Pubmed, Injury lit, Google, Websites, 'Grey' literature). Results of each search were compared on differences and potential missed studies were added. First the titles and then abstracts were scanned in order to include relevant studies. In the case of insufficient information obtained from abstracts the full text articles were obtained. Relevant articles were scrutinized and background documents were created. In addition, relevant references of included articles were checked on new and relevant articles (i.e., snowball search).
The outcomes of the study were reviewed by an expert in the field of child safety in the summer of 2010.
Denatonium benzoate : review of efficacy and safety (version 1)
Wendy Klein-Schwartz (1991)
Final report study of aversive agents (version 1)
[Suzanne Barone] (1992)
Effect of education and safety equipment on poisoning-prevention practices and poisoning : systematic review, meta-analysis and meta-regression (version 1.1)
D. Kendrick, S. Smith, A. Sutton, ...[et al.] (2008)
The impact of bittering agents on pediatric ingestions of antifreeze (version 1.1)
N.C. White, T. Litovitz, B.E. Benson ... [et al.] (2009)