Metamucil Drug Interactions

Our pharmacist answers the latest question regarding whether or not Metamucil interacts with certain medications.

Sep 29, 2017

Hubie asked

Will Metamucil affect my medicines of tikosyn and warfarin?


Yes, it is very possible that Metamucil, also known as psyllium fiber, can affect your medications.

It is recommended to separate ALL medications from fiber type supplements due to how fiber can change the absorption properties of drugs.

Fiber typically decreases how quickly something is absorbed and very often can decrease the AMOUNT of drug absorbed as well. The general recommendation is to take your medication either 2 hours BEFORE fiber or 4 hours AFTER to avoid any type of interaction.

The interaction is just a product of how fiber works in general. It absorbs liquid in the GI tract, thereby altering intestinal fluid and electrolyte transport. Absorption of this liquid also causes expansion of the stool, and the resultant bulk facilitates bowel movement. When fiber is taken with drugs, it affects how it is dissolved and how quickly the medication is absorbed, theoretically affect then how much drug you get and how quickly it will be absorbed.

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