Originally Posted by Piglet Boy
What does blood brain barrier mean? All drugs are in the blood stream once we take it right?
Voltaren ( diclofenac) tablet, works on the site of pain due to inflammation.
Panadol ( Paracetamol) works by sort of "blocking' the thing called prostaglandin causing the pain.
Morphine, Codeine etc, They work in our brain, as they can cross the barrier ( yes it's through blood stream).
So, in other words, Morphine and Codeine crosses the Blood Brain Barrier, and have a Psychotropic effect in our brain system, while Voltaren and Panadol do not.
Another example is,
Cold and flu medication, a decongestant, called Pseudoephedrine ( could be Ephedrine, as Ephedrine is somewhat stronger in effect ), to constrict the lining of our inner side of nose passage.
Once taken, it has an effect like stimulant. ( As it crosses blood brain barrier).
Nowadays, Phenylephrine is used to replaced Ephedrine and Pseudoephedrine, and Phenylephrine less likely to have an effect in our brain. ( So it does not cross the blood brain barrier, and have a psychotropic effect).
The same with Propranolol and other beta-blockers.
Doctors here, in Australia, prefer to prescribe Propranolol, as it has an effect to our brain too. ( Honestly, as I am having a Panic disorder, and taking antianxiety medication, I don't find Propranolol helping me.)
But everyone reacts differently, even to the same medication. So it is better to consult with the Doctor as he could adjust the amount of Propranolol that work for you.
I hope this info helps.