University of Otago researchers have found that some
widely used heartburn and peptic ulcer medicines, involving
proton-pump inhibitors, increase the risk of contracting a rare
The study also adds further weight to growing concerns in New
Zealand medical circles about the overprescribing of such
medicines to infants.
The Otago researchers found people who were taking a
proton-pump inhibitor (PPI) - omeprazole, pantoprazole or
lansoprazole - were about five times more likely to be
admitted to hospital with interstitial nephritis than similar
people who were past users of a PPI.
A teaching fellow in the Otago preventive and social medicine
department, Mei-Ling Blank, was the lead author of the study,
which has just been published in the journal Kidney
Study co-author Dr Lianne Parkin, a senior lecturer in the
department, said interstitial nephritis was a ''rare, but
potentially serious condition'', involving inflammation of
PPIs were an ''effective treatment for gastro-oesophageal
reflux and peptic ulcer diseases'', but evidence from New
Zealand and overseas suggested these drugs were sometimes
Otago researchers had found that for every 100,000 people
taking a PPI, about 12 per year developed interstitial
nephritis, compared with two per 100,000 among past users.
Although the PPIs included in the Otago study were
''extremely safe for the vast majority of users'',
prescribers should be aware of the increased risk of
interstitial nephritis, and patients should seek appropriate
advice before using these medicines.
Other Otago University colleagues had earlier raised concern
about the overuse of PPIs among infants, in a study titled
''Crying and spilling - time to end the overmedicalisation of
normal infant behaviour'', published in the New Zealand
Medical Journal in 2012.
That study noted many infants had ''periods of unsettledness
or irritability'' in their first months of life, and that
''spilling'', resulting from reflux of gastric contents, was
often seen in infants, as part of a normal pattern that
resolved with the passing of time.
The latest Otago research had found that an average of 4% of
New Zealand infants (children less than 1 year of age) per
year had been prescribed a PPI between 2005 and 2009.
Dr Parkin said PPIs were appropriately prescribed for infants
by paediatricians to deal with some rare conditions.
But the Otago study showed more grounds for avoiding
overprescription of medicines, which were in most cases of
little proven benefit for infants.
The overall ''excess risk'' of interstitial nephritis in
users of PPIs, although low in absolute terms, was important
because PPIs were ''one of the most widely prescribed groups
About 20% of the New Zealand population was dispensed a PPI
at least once between 2005 and 2009, and New Zealanders had
also been able to buy a PPI over the counter, since 2009, she