Expert: Dr.Paul Skett - 12/4/2008

Question
QUESTION: Dr. Skett,

I'm looking to find out if there are drugs, recreational or pharmacological, that would normally not cross the BBB that may leech through when a person is under stress.  It would be interesting to know the consequences as well, but not essential for my needs.

I'm trying to formulate a question for my college class where this occurs, but, from what I've read, we have more problems getting useful medications through the BBB than keeping harmful drugs out.

Any help would be appreciated.  :)

ANSWER: Hi, Jennifer,

Thanks for your question.

Stress (mental) doesn't do much to the BBB. Needs to be physical stress to the barrier - one good example is inflammatory diseases of brain (e.g. encephalitis) - this causes gaps to appear between cells lining capillaries in brain (this is what the BBB is) and, thus, substances that would not normally cross into the brain can now get in.

Any use?

Paul



---------- FOLLOW-UP ----------

QUESTION: Very useful!  I had assumed my professor had meant mental stress. (Maybe because of my own "end of semester" stress!)

Could you give me an example or two of drugs that would not normally cross that would do so in that situation?  Thanks!

Answer
Hi, Jennifer,

Thanks for follow-up question.

One good example is penicillin - thus, can be used in such conditions although it would not normal reach its site of action. Can then cause convulsions.

Other is isoprenaline (isoproterenol) - epinephrine analogue - normally confined to peripheral effects in body but when BBB compromised will give central (CNS) effects.

Any use?

Paul