T – Taste
The palatability of medicines for children needs to be considered, as unpleasant tastes can make drug administration a challenge and have an impact on adherence to treatment (Davies, 2021).
Suspensions – usually particles of pharmaceutical material suspended in a liquid, with sweeteners, flavouring agents and preservatives – can usually help reduce the amount of unpleasant tastes (Davies and Tuleu, 2008). However, solutions, which can include thicker sugary syrups, tend to be a more homogenous mixture that dissolves one substance into another, and may be preferred due to the texture and reliability of dose uniformity (Davies and Tuleu, 2008).
Children's taste buds are recognisable from around 15 weeks' gestation (Northcutt, 2004), and infants are born preferring sweeter tastes (such as breast milk) and have a natural aversion to bitter tastes, resulting in children naturally not being able to swallow bitter tasting medicines. Smell and texture are also important factors to consider as well as taste (Rieder, 2018). Other factors – as well as taste, smell and texture – can also affect medication acceptability, and these variables can often interact with each other (see Figure 1).
Developments in taste-marking of oral medications are continuing, focusing on adding different tastes to the solution (i.e. to make a sugary syrup), with a recent systematic review demonstrating palatability of oral dosage developments (Squires et al, 2013), and also creating barriers between the drug and the taste buds, such as encapsulation. However, adding ‘pleasant’ flavours like bubble gum may not actually be that effective in masking taste, (Mennella et al, 2013), leaving – in effect – a very bitter taste in one's mouth.
Recent surveys have explored the awareness of palatability in drug development (Thompson et al, 2013), although little progress has actually been made regarding such challenges, leading to no innovative breakthrough. For now, prescribers need to be aware of the tastes and textures of the solutions or suspensions they wish to prescribe. For example, penicillins, such as oral penicillin V, or flucloxacillin (Davies, 2021), propylthiouracil for hyperthyroidism (Nguyen et al, 2024), and also salty sodium chloride additives. However, different reactions have been noted in different people, potentially vomiting or choking, and genetic variations in taste receptor biology may be key (Mennella and Bobowski, 2015).
Alternatively, prescribers may want to consider different formulations for their prescription, if the taste of the suspension / solution is known to be unpleasant. Younger children – from the age of 6 years – have been shown to be able to swallow tablets (Davies, 2021), and in some instances, from 3 years of age (Davies, 2024), and research has been developed in this field further (Tse et al, 2020). The authors note that nurses and prescribers naturally teach inhaler techniques, so believe that children should be taught to swallow tablets as an essential life skill, emphasising the simplicity and cost savings.
Ultimately, more focus needs to be given to drug development concerning taste and palatability (Squires et al, 2013), alongside an international consensus among industry practices. Currently, prescribers need to be aware of the current difficulties children may be presented with to ensure optimum adherence to medication regimes.
Next in the series will be: U – UTIs.