Friday, 14 April 2017

Cimetidine cross the BBB?


My Naturopath would like me to start taking modified citrus pectin before surgery. She says this will make cells more sticky. I was curious to see if this would cross the blood brain barrier and all I could find said no.

Then I made the connection to cimetidine and that there is a similar logic behind its use. My question is, does cimetidine cross the BBB? If not, how can I help to facilitate it crossing the BBB? Would a proton pump inhibitor do this? (Sorry if I've got that wrong, I'm trying to put lots together.) My partner was reading that inhaling products can help them cross the BBB. It seems like if it were that simple, that's how it would be done. But I do recall reading about a drug that is delivered through a nasal spray to help get it across the BBB.



  1. Cimetidine does penetrate into the central nervous system, with concentrations of 100 micrograms/litre (~400 nanomolar) being detected in the cerebrospinal fluid after oral doses of 1000 mg daily (200+200+200+400 mg). Concentrations as low as 100 nanomolar inhibited glioma cell migration in vitro.

    While proton pump inhibitors are used for some of the same disorders as cimetidine, they are completely different molecules with different cellular targets. Cimetidine and related drugs are histamine receptor H2 antagonists. Cimetidine can also have beneficial effects on the immune system (as an inhibitor of myeloid derived suppressor cells), and in this aspect could potentially be useful even without crossing the BBB.

    1. Thank you for your time, Stephen. So it would make sense for me to start taking it about 7 days before surgery at the doses you described? Should I then continue a maintenance dose?


    2. I'm not aware of any relationship between cimetidine and modified citrus pectin. However, taking cimetidine for several days prior to surgery did seem to lead to better outcomes in a trial for colon cancer.