Glucomannan - WelChol (Colesevelam) Interaction

Interaction Details

Colesevelam is classified as belonging to the following category: Oral Drugs

Theoretically, glucomannan may decrease absorption of drugs taken orally.
Due to its viscosity and bulking effects, there is concern that glucomannan can decrease the absorption of oral drugs. A small clinical study in healthy volunteers shows that taking glyburide 2.5 mg plus glucomannan 3.9 grams with breakfast reduces plasma levels of glyburide when compared with breakfast and glyburide alone. In addition, animal research demonstrates this effect on amoxicillin, but shows increased absorption of metronidazole. This mouse model also demonstrates that metronidazole elimination is prolonged, but amoxicillin elimination is enhanced by 38%; glucomannan may also affect the distribution of some drugs. To avoid changes in absorption, take glucomannan 30-60 minutes after taking oral drugs.

Interaction Rating

Likelihood of Occurrence

Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.

References

• Shima K, Tanaka A, Ikegami H, et al. Effect of dietary fiber, glucomannan, on absorption of sulfonylurea in man. Horm Metab Res 1983;15:1-3.
• Zhang Y, Aldamarany WAS, Song G, et al. Influence of konjac glucomannan and its derivatives on the oral pharmacokinetics of antimicrobial agent in antibiotics cocktails: Keep vigilant on dietary fiber supplement. Int J Biol Macromol 2023;251:126306.

Colesevelam Overview

• Colesevelam is used in adults along with diet, weight loss, and exercise to reduce the amount of cholesterol and certain fatty substances in the blood alone or in combination with other cholesterol-lowering medications known as HMG-CoA reductase inhibitors (statins). Colesevelam is also used alone or in combination with HMG-CoA reductase inhibitors in certain boys and in girls, ages 10 to 17, with familial heterozygous hypercholesterolemia (an inherited condition in which cholesterol cannot be removed from the body normally) to decrease the amount of cholesterol and other fatty substances in the blood. Colesevelam is also used along with diet and exercise to control blood sugar levels in adults with type 2 diabetes (condition in which the body does not use insulin normally and therefore cannot control the amount of sugar in the blood). Colesevelam is in a class of medications called bile acid sequestrants. It works by binding bile acids in your intestines to form a product that is removed from the body.

• Bile acids are made when cholesterol is broken down in your body. Removing these bile acids helps to lower your blood cholesterol. Accumulation of cholesterol and fats along the walls of your arteries (a process known as atherosclerosis) decreases blood flow and, therefore, the oxygen supply to your heart, brain, and other parts of your body. Lowering your blood level of cholesterol and fats may help prevent heart disease, angina (chest pain), strokes, and heart attacks.

Glucomannan - More Interactions

Glucomannan interacts with 1987 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.