Pharmacist issues urgent warning to millions taking metformin over hidden side-effect

Pharmacist issues urgent warning to millions taking metformin over hidden side-effect More than three million people take metformin for type 2 diabetes with more than 26 million prescriptions dispensed every year A pharmacist is urging people taking metformin for diabetes to look out for some key symptoms as they could be masking a common but potentially serious side effect. More than three million people are prescribed metformin to treat the blood sugar disorder with more than 26 million prescriptions dispensed in a year. Now Raj R Patel, posting on TikTok as Pharmacist Health Raj, is alerting people to one side effect which affects up to one in 10 people but that can be easily missed as being just part of their diabetes. In his post the pharmacist said: "If you take metformin and develop new tiredness, weakness or pins and needles, don’t automatically assume it is your diabetes or simply getting older. "There is another possibility worth checking: vitamin B12 deficiency. Metformin is an important and effective treatment for type 2 diabetes. It can improve blood glucose while, in some people, gradually reducing the amount of vitamin B12 available to the body. "The MHRA now classifies reduced vitamin B12 levels or B12 deficiency as a common side effect of metformin, potentially affecting up to 1 in 10 people. The likelihood increases with higher metformin doses, longer treatment duration and existing risk factors for B12 deficiency." The expert went on to explain why it was important that B12 was checked - and what difference it makes. He said: "Vitamin B12 is important for healthy blood cells and the nervous system." He warned low levels could cause symptoms including: - extreme tiredness - pins and needles - numbness or altered sensation - a sore, red tongue - pale or yellow-looking skin - anaemia - neurological symptoms He added: "Here is the important clinical point: some of these symptoms can also be caused by diabetes itself. For example, pins and needles in the feet might be assumed to be diabetic neuropathy when vitamin B12 deficiency is another possibility that deserves consideration. "That is why improving blood glucose does not automatically tell us everything else is fine. Your HbA1c and your vitamin B12 level measure completely different things." He said it was not necessary for everybody taking metformin to automatically have regular B12 tests but there were times when it was needed. He explained: "Current MHRA advice is to check vitamin B12 when deficiency is suspected, including when someone develops new neuropathy or anaemia. "Periodic monitoring should also be considered in people who have additional risk factors for B12 deficiency." He said risk can be higher with: • longer-term metformin treatment • higher doses • already low-normal B12 levels • vegan or some vegetarian diets • conditions affecting B12 absorption • medicines such as proton-pump inhibitors that can also reduce B12 absorption But he also cautioned: "Please don’t stop metformin because you are worried about B12. If deficiency is confirmed, it can usually be treated while metformin continues if the medicine remains appropriate and tolerated. That is specifically reflected in MHRA guidance. "The NHS also advises speaking to a pharmacist or doctor about troublesome side effects rather than stopping metformin without advice." He added: "Your diabetes numbers can improve while something else changes quietly in the background. That doesn’t make metformin a bad medicine. It means good treatment includes monitoring the person — not just the blood sugar."