Glucomannan - Venclexta (Venetoclax) Interaction
Herbal: Glucomannan
Also Known As: Glucomanano, Glucomannane, Konjac, Konjac Mannan
Drug: Venetoclax
Brand names:
Venclexta
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
May 25, 2025
Interaction Details
Venetoclax 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
ProbableInteraction 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.
Glucomannan Overview
Glucomannan is a type of soluble fiber that comes from the konjac root, which is native to Asia. It is often used as a dietary supplement to promote weight loss and improve digestive health. When glucomannan is mixed with a liquid, it forms a gel-like substance that can help to reduce appetite by promoting a feeling of fullness. It can also help to regulate bowel movements and relieve constipation. Some studies have suggested that glucomannan may be effective for weight loss and it is a common ingredient in weight loss products, such as Lipozene.
Venetoclax Overview
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Venetoclax is used alone or in combination with obinutuzumab (Gazyva) or rituximab (Rituxan) to treat certain types of chronic lymphocytic leukemia (CLL; a type of cancer that begins in the white blood cells) or certain types of small lymphocytic lymphoma (SLL; a type of cancer that begins mostly in the lymph nodes). It is also used in combination with either azacitidine (Vidaza), decitabine (Dacogen), or cytarabine as a first treatment for acute myeloid leukemia (AML; a type of cancer that begins in the white blood cells) in people 75 years of age or older, or in adults who have medical conditions that prevents them from being treated with other chemotherapy medications. Venetoclax is in a class of medications called B-cell lymphoma-2 (BCL-2) inhibitors. It works by blocking the action of a certain protein in the body that helps cancer cells survive. This helps to kill cancer cells.
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.
| Major | The combined use of these agents is strongly discouraged as serious side effects or other negative outcomes could occur. |
| Moderate | Use cautiously under the care of a healthcare professional or avoid this combination. A significant interaction or negative outcome could occur. |
| Minor | Be aware that there is a chance of an interaction. Watch for warning signs of a potential interaction. |
| Unknown | No interactions have been reported or no interaction data is currently available. |
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Parts of this content are provided by the Therapeutic Research Center, LLC.
DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.
© 2021 Therapeutic Research Center, LLC
Drug descriptions are provided by MedlinePlus.
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