Drs/Medical ppl, need couple clarrifications pls... :) (answer and become my hero!)?

Question

If you know any of the following -

1) MgSO4 is used for eclampsia fits to stabilise the brain, why dont they use Na drugs instead (eg- Na Valporate) conversely why dont they use Mag Sulfate for epilepsy?

2) Calcium gluconate is used to avoid arrhythmias in hypokalaemia, can it be used for the same in hyperkalaemia?

3) Aortic Stenois is a danger for anethetics, something to do with preload - can you explain why AS is dangerous for anesthetics?

I have read around the above, but just require clarrification from someone smarter than me :)

Thanks in advance!!!!!!

Answer 1

1)MgSO4 acts not only to prevent seizures, but to lower BP as well.  It has a lot of side effects, so it's not suitable for everyday use in epileptics.

3)  AS is dangerous, because almost every drug we give in anesthesia causes vasodilation.  With limited outflow from the aorta, BP can drop precipitously.  We have to be very careful to maintain vascular tone in these people.  Keeping preload up helps with filling during diastole in hearts that are poorly compliant.

Read more here:

http://64.233.169.104/search?q=cache:jP7...

Hope that helps somewhat.