According to the World Health Organization, around half of all pediatric patients do not take their medicines correctly (1). “Taste is the number one issue,” says Julie Mennella, researcher at the Monell Chemical Senses Center. “Young children often can’t swallow pills and tablets, which encapsulate the bitter tasting drug or active pharmaceutical ingredient. This means they instead have to take bitter-tasting liquids, which have flavor ingredients to mask the bad taste, but they don’t always work for all children.” When Mennella attended a lecture at the University of Pennsylvania, she met Elizabeth Lowenthal from the university’s Perelman School of Medicine. “Elizabeth relayed issues encountered when giving Kaletra, a pediatric HIV drug, to infants: some infants accepted it readily while others strongly rejected it. It sparked off an interesting conversation about why some people find medicines unpalatable, and we formed a collaboration to investigate whether we could see the same variation in adults,” says Mennella.
The researchers used a panel of genotyped adults to document the range of individual differences in the taste and palatability of the liquid formulation of Kaletra, which contains a number of flavor ingredients including sugars, salts and menthol. Panelists rated their taste sensations, which the researchers used to determine a genotype-phenotype relationship. The results showed that those who experienced less bitter and sweeter taste sensations had a different genetic signature than other participants. Bitterness and irritation ratings of Kaletra varied by the orphaned bitter receptor gene (TAS2R60), whereas sweetness ratings of Kaletra varied according to the cold receptor gene (TRPM8), which is activated by menthol, an excipient of Kaletra (2). “Essentially, we systematically used the adult palate as a screening tool to identify those drugs where there is wide variation in acceptance to uncover a genetic basis,” says Mennella. “Our hope is that this knowledge may lead to molecular targets to improve taste, as well as systematic assessment of other pediatric drugs to determine which ones are problematic for some children. A drug, no matter how powerful, is not going to work if the child rejects its taste.”
Read more about the challenges of pediatric medicines on HERE. This research was supported by a grant from the National Institute of Deafness and Other Communication Disorders (NIDCD).
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References
- World Health Organization, “Adherence to Long-Term Therapies: Evidence for Action”, (2003). Last accessed January 08, 2018. Available at: http://bit.ly/2ElL9IH. JA Menella, PS Mathew, and ED Lowenthal, “Use of adult sensory panel to study individual differences in the palatability of a pediatric HIV treatment drug”, Clin Ther, 39, 2018-2058 (2017). PMID: 28923290.
