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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 6 of 6. This is the beginning of the thread.
Posted by Phillipa on October 26, 2010, at 12:37:06
Okay if you swallow a medication any kind and it goes through the digestive tract can understand how some depending on individual would upset stomach and digestion. But taking an lets say antibiotic enter then the blood stream and hit an infection and kill or destroy the targeted germs. But even antibiotics cross the blood brain barrier and can can damage as the biaxin took my taste and smell permanently away. But how and what is the blood brain barrier and how does a medication psychiatic or otherwise cross it to do something. I just don't understand what a blood barrier is. I picture a road block stopping a med from entering. Is it possible a med can't cross it and that is why meds work for some and not others. My thoughts today as I get so confused. Phillipa
Posted by ed_uk2010 on October 26, 2010, at 15:48:34
In reply to Simple Question But Can't Understand, posted by Phillipa on October 26, 2010, at 12:37:06
The term 'blood brain barrier' refers to the way in which certain molecules are prevented from passing from the blood stream into the central nervous system. The barrier consists of tight junctions around the tiny blood vessels (capillaries) which supply the brain with nutrients and oxygen. Large molecules, including some drugs, cannot penetrate the barrier.
>Is it possible a med can't cross it and that is why meds work for some and not others.
All commonly used psychiatric drugs readily pass the BBB. This is not the reason for lack of response.
Posted by bleauberry on October 26, 2010, at 16:21:58
In reply to Simple Question But Can't Understand, posted by Phillipa on October 26, 2010, at 12:37:06
Most antibiotics do not cross the blood brain barrier. Some do.
The barrier is sort of like a filter. If a substance molecule is too big, it won't fit through the filter.
If there is damage to the barrier, say for example from heavy metals or from borellia (they eat collagen soft tissue and that's all they do), then bad stuff that shouldn't get through will.
Posted by Phillipa on October 26, 2010, at 20:59:48
In reply to Re: Simple Question But Can't Understand, posted by bleauberry on October 26, 2010, at 16:21:58
What about say bacterial meningitis? Just the spinal fluid? But doesn't that pass through brain stem via spianl columm into the brain? Meds are really complicated. Phillipa
Posted by ed_uk2010 on October 27, 2010, at 17:26:15
In reply to Re: Simple Question But Can't Understand, posted by Phillipa on October 26, 2010, at 20:59:48
> What about say bacterial meningitis? Just the spinal fluid? But doesn't that pass through brain stem via spianl columm into the brain? Meds are really complicated. Phillipa
I'm not sure what the question is... but the permeability of the blood brain barrier is increased in bacterial meningitis. Antibiotics such as penicillin G and cefotaxime which normally penetrate poorly are able to penetrate relatively well during the acute phase of the illness. A small number of antibiotics such as chloramphenicol penetrate the BBB very well. Due to the risks of chloramphenicol injection, it is only used occasionally - for life threatenening infections. IIRC, sulfonamines penetrate the BBB very well. Back in the days when meningococci were highly sensitive to sulfonamines, they were very effective for meningococcal meningitis.
Posted by Phillipa on October 27, 2010, at 20:34:49
In reply to Re: Simple Question But Can't Understand, posted by ed_uk2010 on October 27, 2010, at 17:26:15
Ed you got it and sorry for the spelling my nephew had spinal bacterial meningitis at age 2. Fine now also. All grown up with a family now. Phillipa
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