Dr Kevin Thomas from the Norwegian Institute of Water Research in Oslo, Norway, and his team published their findings in the journal Science of the Total Environment.
Dr Thomas told GP that the researchers were now using the same methods, combined with prescribing data, to look at adherence to prescribed medicine at local and national levels. The use of urinary biomarkers means the researchers can measure the levels of drugs metabolised by the body, rather than simply disposed of unconsumed.
The group has already looked at whether use of the antihistamine cetirazine can be shown to be correlated with pollen levels with this method, but has not yet published its findings.
‘Comparing what we measure from sewage with prescription rates can tell us if and when people are taking their medicines,’ he said.
‘For some medicines we'd imagine that they are taken quite reliably, however, other medicines may not be taken so reliably due to various factors.’
Dr Thomas suggests that long-term monitoring, coupled with prescribing data, could allow healthcare managers to see how much of a drug is actually being used. Comparisons could also be made between different local areas, he said.
‘The sampling is the key part as it can be tailored to the question,’ he said. ‘For example, if you want to know that a prescription medicine may be being used recreationally then one would look at high resolution sampling over a week or a series of weeks to see whether the excretion pattern from a population deviates significantly from what would be expected.'
'These are the sorts of questions I think that we can possibly help answer with such an approach.'