Metformin and omeprazole are two commonly prescribed medications used to treat different health conditions. Metformin helps control blood sugar levels in people with diabetes, while omeprazole reduces stomach acid and is often prescribed for acid reflux, heartburn, and stomach ulcers.
Although both medications can be beneficial when used appropriately, there is an important issue worth understanding: long-term use of metformin and omeprazole may contribute to low vitamin B12 levels.
This does not mean that everyone taking these medicines will develop a deficiency, or that the medications should never be taken together. However, knowing the possible risks can help patients have more informed conversations with their healthcare professionals.
What Is Metformin Used For?
Metformin is a medication primarily prescribed to help manage type 2 diabetes. It works by reducing glucose production in the liver and improving the body’s response to insulin.
Doctors may prescribe metformin alone or alongside other diabetes treatments. It is widely used because it can help control blood sugar levels when taken as directed.
Common side effects include nausea, diarrhea, stomach discomfort, and reduced appetite. Long-term treatment can also lower vitamin B12 levels in some people. The risk is greater with higher doses, longer treatment duration, and certain existing risk factors.
According to the UK’s Medicines and Healthcare products Regulatory Agency (MHRA), vitamin B12 deficiency is a common side effect of metformin and should be considered when patients develop suggestive symptoms.
What Is Omeprazole Used For?
Omeprazole belongs to a group of medicines called proton pump inhibitors (PPIs). These medications reduce the amount of acid produced by the stomach.
Doctors commonly prescribe omeprazole for:
- Gastroesophageal reflux disease (GERD).
- Frequent heartburn and acid reflux.
- Stomach and duodenal ulcers.
- Certain conditions involving excessive stomach acid.
- Protection against stomach ulcers in some people taking particular medications.
Omeprazole can relieve symptoms and help damaged tissue heal. However, prolonged use may affect the absorption of certain nutrients, including vitamin B12, in some individuals.
People who need long-term treatment should have their medication reviewed periodically to confirm that the dose and duration remain appropriate.
Why Can Taking Both Medicines Matter?
The main concern is their potential combined effect on vitamin B12 levels.
Vitamin B12 is essential for healthy red blood cells, normal nerve function, and DNA production. The body obtains it from foods such as meat, fish, eggs, dairy products, and fortified foods.
Metformin can interfere with vitamin B12 absorption. Omeprazole reduces stomach acid, which helps the body release vitamin B12 from food. When both medicines are taken over a prolonged period, some patients may have a greater risk of developing a deficiency.
Research has investigated this association, although the size of the additional risk varies between studies. Not everyone taking both medicines will develop low vitamin B12 levels.
The important point is that this combination may warrant closer attention to vitamin B12 status, particularly in people with additional risk factors.
What Are the Symptoms of Vitamin B12 Deficiency?
Vitamin B12 deficiency can develop gradually, and symptoms may be mistaken for tiredness, aging, or other medical problems.
Possible warning signs include:
1. Unusual Tiredness or Weakness
Low vitamin B12 can contribute to anemia, which may cause persistent fatigue, weakness, or reduced energy
