Metformin with Glucosamine Interaction Details

Brand Names Associated with Metformin

Medical Content Editor Dr. Brian Staiger, PharmD
Last updated Nov 05, 2023

Interaction Effect

Reduced antidiabetic agent effectiveness

Interaction Summary

Glucosamine did not affect hemoglobin A1c in a randomized, double-blind, placebo-controlled trial of 34 patients with well-controlled type 2 diabetes mellitus. The results of this trial may not apply to patients with uncontrolled diabetes. The Arthritis Foundation has recommended that patients with diabetes monitor their blood glucose more frequently when taking glucosamine (Anon, 2002). Clinical studies are inconclusive regarding the effect of glucosamine on glucose and insulin sensitivity .

Severity

Minor

Onset

Rapid

Evidence

Theoretical

How To Manage Interaction

Glucosamine is likely safe in patients with well-controlled diabetes (HbA1c less than 6.5%) taking one or two oral antidiabetic medications or controlled by diet only. In patients with higher HbA1c levels or those taking insulin, monitor blood glucose levels closely.

Mechanism Of Interaction

Glucosamine may impair insulin secretion through competitive inhibition of glucokinase in pancreatic beta cells and/or alteration of peripheral glucose uptake

Literature Reports

A) Glucosamine did not significantly affect hemoglobin A1c (HbA1c) in a randomized, double-blind, placebo-controlled trial of 34 patients with well-controlled type 2 diabetes mellitus. Patients received glucosamine (Cosamin DS) 1500 milligrams (mg) (n=22) or placebo (n=12) daily for 90 days. The Cosamin DS also contained chondroitin sulfate 400 mg, manganese 5 mg, and ascorbic acid 66 mg. HbA1c increased from a mean baseline of 6.45% to 6.5% in the glucosamine group, and decreased from a mean baseline of 6.25% to 6.09% in the placebo group (not significant). The study had 80% power to detect a difference of greater than 0.3% between groups, and 80% power to detect a difference of 0.15% from before to after treatment in the glucosamine group .

B) In a trial of 212 patients without diabetes taking glucosamine for knee osteoarthritis, blood glucose levels were slightly decreased after 3 years versus placebo . In a second three-year study of 202 patients without diabetes, 3 patients taking placebo and one patient taking glucosamine were diagnosed with diabetes . In 15 patients without diabetes, 12 weeks of glucosamine treatment did not affect fasting glucose, but did increase fasting insulin versus placebo (p = 0.01) . In 5 healthy subjects, intravenous glucosamine sulfate reduced glucose tolerance and insulin sensitivity under hyperglycemic conditions , whereas glucosamine infusion did not affect insulin-induced glucose uptake in 18 healthy subjects .

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.

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Definitions

Severity Categories

Contraindicated

These drugs, generally, should not be used together simultaneously due to the high risk of severe adverse effects. Combining these medications can lead to dangerous health outcomes and should be strictly avoided unless otherwise instructed by your provider.

Major

This interaction could result in very serious and potentially life-threatening consequences. If you are taking this drug combination, it is very important to be under close medical supervision to minimize severe side effects and ensure your safety. It may be necessary to change a medication or dosage to prevent harm.

Moderate

This interaction has the potential to worsen your medical condition or alter the effectiveness of your treatment. It's important that you are monitored closely and you potentially may need to make adjustments in your treatment plan or drug dosage to maintain optimal health.

Minor

While this interaction is unlikely to cause significant problems, it could intensify side effects or reduce the effectiveness of one or both medications. Monitoring for changes in symptoms and your condition is recommended, and adjustments may be made if needed to manage any increased or more pronounced side effects.

Onset

Rapid: Onset of drug interaction typically occurs within 24 hours of co-administration.

Delayed: Onset of drug interaction typically occurs more than 24 hours after co-administration.

Evidence

Level of documentation of the interaction.

Established: The interaction is documented and substantiated in peer-reviewed medical literature.

Theoretical: This interaction is not fully supported by current medical evidence or well-documented sources, but it is based on known drug mechanisms, drug effects, and other relevant information.

How To Manage The Interaction

Provides a detailed discussion on how patients and clinicians can approach the identified drug interaction as well as offers guidance on what to expect and strategies to potentially mitigate the effects of the interaction. This may include recommendations on adjusting medication dosages, altering the timing of drug administration, or closely monitoring for specific symptoms.

It's important to note that all medical situations are unique, and management approaches should be tailored to individual circumstances. Patients should always consult their healthcare provider for personalized advice and guidance on managing drug interactions effectively.

Mechanism Of Interaction

The theorized or clinically determined reason (i.e., mechanism) why the drug-drug interaction occurs.

Disclaimer: The information provided on this page is for informational purposes only and should not be considered medical advice. Always consult with a qualified healthcare professional regarding your specific circumstances and medical conditions.

Where Does Our Information Come From?

Information for our drug interactions is compiled from several drug compendia, including:

• Gold Standard Drug Database
• Micromedex
• Lexicomp
• DrugBank

The prescribing information for each drug, as published on DailyMED, is also used. 

Individual drug-drug interaction detail pages contain references specific to that interaction. You can click on the reference number within brackets '[]' to see what reference was utilized.

The information posted is fact-checked by HelloPharmacist clinicians and reviewed quarterly.