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Potassium, Fiber Interaction And Gallbladder Removal Concerns

In our latest question and answer, the pharmacist discusses concerns regarding an interaction with fiber and potassium.


I read the following: 'It [Metamucil] should be taken at least 2 hours before or 2 hours after other oral medications.' With regard to this, each morning I have to take one tablet of slow-release Span-K potassium chloride 600mg with food. I've had my gall bladder removed and was wondering if I should extend the range to 2½ to 3 hours before consuming Metamucil? This assumption is based on the fact that once a gall bladder has been removed, it takes the stomach longer to process food, especially fatty foods. Thank you."

Asked by John On Apr 01, 2024

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Apr 01, 2024
Last updated Jun 09, 2024


Hello and thank you for your question!

It is indeed recommended to separate the administration of oral medications and fiber, such as Metamucil, by at least 2 hours to avoid potential interactions that could reduce drug absorption. This is because psyllium, the active ingredient in Metamucil, forms a gel-like substance in the gut, which can bind to drugs and potentially reduce their effectiveness.

In regards to your specific situation with taking slow-release Span-K potassium chloride 600mg with food, there is no evidence to suggest that you need to broaden the separation range beyond the recommended 2 hours.

Although the gallbladder plays a role in the digestion and absorption of fats, its removal does not directly impact the absorption of medications like potassium.

The removal of the gallbladder could certainly affect some things, like the absorption of fat-soluble vitamins, like Vitamin A and vitamin E, but again, there shouldn't be a significant impact on potassium absorption.

Potassium is mainly absorbed in the small intestine through passive and active transport mechanisms, which are not significantly affected by the reduction in bile production resulting from gallbladder removal. Based on this, it is safe to continue following the advice to separate your potassium medication and fiber by at least 2 hours to avoid any potential interactions.

Final Words

To summarize, while the removal of your gallbladder may affect the absorption of certain nutrients, it does not impact the absorption of medications like potassium.

Therefore, there is no need to extend the separation time beyond the recommended 2 hours when taking Metamucil and your potassium medication.

Thanks again for reaching out and please do so again anytime!


  • Potassium Chloride Prescribing Information, AccessFDA
  • Effects of pharmacological fiber supplements on levothyroxine absorption, PubMed

About the Pharmacist

Dr. Brian Staiger, PharmD

Dr. Brian has been practicing pharmacy for over 13 years and has wide-ranging experiences in many different areas of the profession. From retail, clinical, program development, and administrative responsibilities, he's your knowledgeable and go-to source for all your pharmacy and medication-related questions! Dr. Brian Staiger also has herbalist training and educational certificates in the field of medical ethnobotany. Feel free to send him an email at [email protected]! You can also connect with Dr. Brian Staiger on LinkedIn.

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