New insights into why people get side effects with the most commonly prescribed diabetes drug
Published On Tue 16 Dec 2014 by Grant Hill
A study by the University of Dundee has revealed why some patients taking the most commonly prescribed diabetes drug are susceptible to suffering gastrointestinal side effects.
Researchers say their findings suggest patients who are suffering side effects from taking metformin should review their prescribed treatment with their GP.
Metformin is the medication of choice for most patients with type 2 diabetes and is used by about 1.5 million people in the UK. Metformin has many benefits over other diabetes therapies, yet approximately 1 in 4 patients suffer gastrointestinal side effects with this pill, and for 1 in 20 patients these side effects are so severe metformin cannot be used.
The reason why some patients develop such bad side effects has not been understood. Researchers at the University of Dundee have provided new insight into why some patients develop these side effects, and importantly how some other commonly used treatments may increase the risk of getting these side effects.
The results of the work are published in the journal Diabetes.
Ms Tanja Dujic, who undertook this work at the Medical Research Institute at the University of Dundee, explained, “Metformin is absorbed from the gut, in part, by a transporter called OCT1. Eight per cent of the population carry genetic variants that result in markedly reduced function of this OCT1 transporter. We showed that these people are nearly twice as likely to develop gastrointestinal side effects with metformin than people with normal OCT1 function.”
However, it’s not all down to our genetics - other prescribed drugs can also increase the risk of these side effects occurring.
Professor Ewan Pearson, who led the study, said, “There are a number of commonly used drugs, including anti-acid drugs such as omeprazole, and some blood pressure treatments such as doxazosin or verapamil, that also interact with the OCT1 transporter. People taking these drugs are also twice as likely to get side effects from metformin. And if you are one of the eight per cent who are genetically susceptible and are also taking one of these drugs your risks of side effects are increased more than four-fold.”
Professor Pearson said patients who are suffering side effects from taking metformin should review their other prescribed treatment with their GP.
“We do need to follow up this observation with a careful clinical trial, but our findings certainly suggest that if you are suffering with gastrointestinal side effects whilst being treated with metformin, it would be worthwhile reviewing your other treatment with your GP, as one of them may be making the problem worse,” he said.
He added, “This work has used anonymous data from patients with type 2 diabetes in Tayside, Scotland, who have consented for us to analyse their DNA and medical records. We are extremely grateful to them for taking part in this GoDARTS study.”
This research provides new leads towards safer diabetes treatments, underlining the importance of personalised treatment in type 2 diabetes. If anyone has had side effects from metformin and they want to take part in research into this, they can sign up at http://www.goshareadr.org.
For media enquiries contact:
Grant Hill
Press Officer
University of Dundee
Nethergate, Dundee, DD1 4HN
TEL: 01382 384768
E-MAIL: g.hill@dundee.ac.uk
MOBILE: 07854 953277