brain/blood, blood/brain
 

Can someone explain that one to me. I get the basics. Some chemos get to our brains and some don't. How do I know which drugs do and which don't, or if the chemo and herceptin I had crosses or doesn't cross?

Hey Pink

There is a list somewhere on this board. From your signature, only the "F" passed the blood brain barrier as it is the same active that Xeloda turns into after it passes through the liver. All others are molecularly too large to do so. I will try to find the list that does and doesn't (tamoxifen does)and try to post it.

<DIR>Yes, there was a wonderful detailed post or two, somewhere... and some of which I'd saved in a 'safe' place... so safe I can't find it!

It has to do with moleculer Wgt. You can google a drug name+molecular wgt. and have some luck finding an answer. The 'limit' is around a high 300. So, technically, Xeloda is small enough to pass the bbb. And has for me, we think, in combo with the Temodar.

here is just a tiny bit of what I could find and other than Tykerb, I know of no others to be small enough:

GEMZAR : molecular wgt.= 299.66
TEMODAR : molecular wgt.= 194.15
XELODA : molecular wgt.= 359.35

then there's the disscussion of 'leaky' bbb caused by the tumor or radiation... allowing possibly other larger wgts to enter brain.

oh, I think one of the platinums has been used with some small success. But my brain is just 'leaky' and not sure ........phooey.
pattyz



</DIR>

My doc tells me that Carboplatin can also cross the BBB. And I believe Cisplatin as well (that's what Lance Armstrong got after his brain surgery).

I think very simplistically it's a matter of the blood vessels getting smaller in diameter from the body through the neck to the brain, and if the chemo/targeted agent is too large a molecule, then it can't make it through.

Herceptin currently doesn't, but they are working on a smaller molecule version as we speak.

Thanks for sharing that Amy. Wow, that news kind of bums me. I guess I should have known that none of my chemo went to my brain BUT I didn't know that. I thought for as foggy as I often felt after a chemo cycle it had to have went their. I did dose dense A/C and Taxol. Oh well. Nothing I can do about it now. It's done and overwith and thankfully I do not have brain mets or mets anyplace else. Is praying it stays that way.

Again, thanks for sharing that information with us.

Blessings of Peace,

Marey Jo

Keep in mind that that article is from 2004... it is VERY good info, but some info has evolved since then. And it doesn't have Lapitinib(Tykerb) on the list, which does cross the BBB (and we now believe that Capecetibine(Xeloda) does too, in combo with the Tykerb.

Do they think Xeloda crosses the brain barrier by itself, or does it have to be used with Tykerb..sherryg

Sherry,
Xeloda was used in a small trial/study with Temodar for bc specific brain mets and showed some small but positive response. That is the reason I chose this combo for myself when I'd 'used up' my rad amounts.

And as I've said, technically, Xeloda is small enough to cross the bbb alone. But, as with any of the chemos will it work for an individual?? Don't know for sure until tried.

patty

Tykerb does, Carboplatin does
 

These cross for sure. I'm sure there are more but I don't know them.

For anyone who is interested, I have a link for a good description of the blood/brain barrier with pictures. Molecules are smaller than cells, and red blood cells can go through the tiniest capillaries. The blood/ brain barrier is a protective measure that helps to protect the brain from pathogens and toxins that might be carried in the blood.

http://images.google.com/imgres?imgu...%3Den%26sa%3DX

Leslie