Drug Interaction Report

Limited data suggest that orally administered potassium chloride may decrease the gastrointestinal absorption of vitamin B12. The mechanism is believed to be a reduction in ileal pH by potassium chloride, which significantly decreases the activity of intrinsic factor that is necessary for vitamin B12 absorption. However, the interaction should rarely lead to clinically significant deficiency because the body (primarily the liver) usually has a copious supply of vitamin B12 that can sustain a person for several years in the absence of adequate intake. As for the treatment of B12 deficiency-related anemia, non-oral routes of administration (e.g., parenteral, intranasal, sublingual) are generally preferred, which would bypass the potential interaction.

ADJUST DOSING INTERVAL: Bowel cleansing products can increase the gastrointestinal transit rate. Oral medications administered within one hour of the start of administration of the bowel cleansing solution may be flushed from the gastrointestinal tract and not properly absorbed.

MANAGEMENT: Patients should be advised that absorption of oral medications may be impaired during bowel cleansing treatment. Oral medications (e.g., anticonvulsants, oral contraceptives, antidiabetic agents, antibiotics) should not be administered during and within one hour of starting bowel cleansing treatment whenever possible. However, if concomitant use cannot be avoided, monitoring for reduced therapeutic effects may be advisable.