The recent move to remove sugars from medicines to reduce the risk of dental decay has been welcomed by dentists, but concern has been expressed that the replacement sugars-free medicines might themselves damage teeth. New research reported at the British Pharmaceutical Conference this week indicates that this is not the case.

The research was reported by Wasim Baqir and Anne Maguire, from the Newcastle Dental School, and colleagues from Newcastle Hospitals and Dublin Dental School.

Dr Maguire explained why the work was carried out: "To reformulate medicines without sugars, some products might require addition of weak acids to optimise their palatability and formulation properties. The question was whether this might increase the risk of dental erosion, ie, have we swapped one problem (decay) for another (erosion)?"

Erosion refers to tooth wear produced by chemicals. As the hard surface tissue is worn away, teeth become more sensitive because nerves are exposed. (Tooth wear can also occur from brushing too hard and from grinding teeth.)

Dental erosion becomes a potential issue when medicines with prolonged oral clearance are taken long term for chronic illness. These medicines are most likely to taken by young children and the elderly, who may be unable to swallow solid doses.

"In healthy children, the risk of medicine-induced erosion is low compared with the risk of erosion from acids in fizzy soft drinks, but it is important in chronically sick children who may need more complex dental care because of their underlying medical condition," Dr Maguire commented.

The researchers investigated the erosive potential of 126 formulations by measuring their acidity. All were medicines with prolonged oral clearance, which means they are retained in the mouth for a prolonged period compared with swallowing a tablet. They included liquids/syrups, dispersible or effervescent tablets and chewable tablets. Over 60 per cent were sugars-free.

Overall, there was no statistically significant difference in acidity between the sugars-containing and sugars-free medicines. There was also no difference when acidity was compared in matched pairs of medicines available in bioequivalent sugars-containing and sugars-free formulations.

Dr Maguire said: "We are reassured that making a product sugars-free does not appear to make it more erosive. More useful predictors of whether a medicine might be erosive were found to be the dose form and the therapeutic class of medicine. Effervescent tablets and respiratory medicines were significant predictors of low pH [higher acidity] and dispersible tablets and gastric medicines were significant predictors of high pH [lower acidity]. Proprietary medicines were less likely than generic medicines to be acidic."