Vitamin B12 - Glucophage (Metformin) Interaction

Interaction Details

Metformin is classified as belonging to the following category: Metformin (Glucophage)

Metformin, a common medication used to manage type 2 diabetes, has been associated with lower vitamin B12 levels in some individuals. Prolonged use of metformin can interfere with the absorption of B12 in the digestive system, potentially leading to a deficiency in this essential vitamin.

Interaction Rating

Likelihood of Occurrence

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists

Pharmacist Analysis

It is important to note that this is less an 'interaction' versus a potential result of prolonged metformin use. In many individuals taking metformin, supplementing with vitamin B12 is recommended.

Metformin can lead to a reduction in vitamin B12 levels, primarily depending on the dosage and duration of use. This reduction might potentially result in a deficiency. Metformin's impact on vitamin B12 levels is thought to be related to its potential interference with intrinsic factor secretion or uptake, influence on bowel motility, and the possibility of causing bacterial overgrowth. These factors can collectively contribute to vitamin B12 malabsorption and elevated homocysteine levels.

The risk of deficiency is notably higher in individuals who have been taking higher doses of metformin for an extended period, especially those who are older or follow a vegetarian diet. It's worth mentioning that even if metformin use continues, any deficiency can be corrected with the appropriate vitamin B12 supplementation.

To ensure the well-being of individuals taking metformin chronically, it's advisable to monitor for potential signs and symptoms of vitamin B12 and folic acid deficiency. Additionally, it's recommended to encourage those on metformin to maintain a diet that includes sufficient vitamin B12 and to undergo regular checks of their serum vitamin B12 and homocysteine levels, typically on an annual basis.

Metformin Overview

• Metformin is used alone or with other medications, including insulin, to treat type 2 diabetes (condition in which the body does not use insulin normally and, therefore, cannot control the amount of sugar in the blood). Metformin is in a class of drugs called biguanides. Metformin helps to control the amount of glucose (sugar) in your blood. It decreases the amount of glucose you absorb from your food and the amount of glucose made by your liver. Metformin also increases your body's response to insulin, a natural substance that controls the amount of glucose in the blood. Metformin is not used to treat type 1 diabetes (condition in which the body does not produce insulin and therefore cannot control the amount of sugar in the blood).

• Over time, people who have diabetes and high blood sugar can develop serious or life-threatening complications, including heart disease, stroke, kidney problems, nerve damage, and eye problems. Taking medication(s), making lifestyle changes (e.g., diet, exercise, quitting smoking), and regularly checking your blood sugar may help to manage your diabetes and improve your health. This therapy may also decrease your chances of having a heart attack, stroke, or other diabetes-related complications such as kidney failure, nerve damage (numb, cold legs or feet; decreased sexual ability in men and women), eye problems, including changes or loss of vision, or gum disease. Your doctor and other healthcare providers will talk to you about the best way to manage your diabetes.

Vitamin B12 - More Interactions

Vitamin B12 interacts with 19 drugs

Interaction Rating Key

These severity listings are for informational use only. Never start, stop or otherwise change your therapy before speaking with your provider.