Posted by ed_uk2010 on December 3, 2012, at 18:15:58
In reply to Blood Brain Barrier - any doctors for this?, posted by rjlockhart37 on November 30, 2012, at 15:16:08
>I just found something that finally i have been searching for about the medications not taking effect. The blood brain barrier protects the brain from unknown substances, and things that could be harmful....but I also read it can stop the actions of CNS drugs...
Some drugs which do cross the blood brain barrier are pumped back out of the brain by a molecule called p-glycoprotein (also called multi-drug resistance protein). P-gp activity is controlled by genetics and can be inhibited by various drugs. Some psychiatric drugs are pumped back out of the brain by P-gp, and genetic differences in P-gp activity may partly account for why some people require higher doses of antidepressants than others. Drugs which inhibit P-gp may increase the effects of other drugs which would otherwise be pumped back out of the brain by P-gp. Certain SSRIs such as sertraline (Zoloft), paroxetine (Paxil) and to a lesser extent fluoxetine (Prozac) are believed to be P-gp inhibitors.
I think it's unlikely that the blood brain barrier has any special relevance to your reduced response to medication.
One of the main factors which reduces blood/brain levels of olanzapine (Zyprexa) is smoking. Do you smoke?
poster:ed_uk2010
thread:1032198
URL: http://www.dr-bob.org/babble/20121130/msgs/1032398.html