PDA

View Full Version : antidepressants....mechanism of actions



SONALI SEN
01-07-2007, 03:02 AM
why does MAO inhibitors cause hypotention as their side effects? can anyone explain me this mechanism......:confused:

vibhor
01-07-2007, 06:53 AM
so miss sonali antidepressents acts on d2 reseptors present in our brain
barbiturates are the antid......eg: phenobarbiton,mephobarbiton R SOME



vibhor

vibhor
01-07-2007, 06:54 AM
Actually It Reduces The Stress In Ex So Causes Hypotention

SONALI SEN
01-07-2007, 10:30 AM
see as far as i understand.....MAO inhibitors......increase the release of NE ,serotonin,and dopamine from the presynaptic terminal......and so NE 5HT and DA should increase the sympathetic nervous system and cause hypertension.....but KATZUNG has clealy mentioned that in long run maoi will cause hypotension.
I did not understand how you have tried to explain this....can you make me more clear?????
thanks

banjul10
01-07-2007, 07:57 PM
see as far as i understand.....MAO inhibitors......increase the release of NE ,serotonin,and dopamine from the presynaptic terminal......and so NE 5HT and DA should increase the sympathetic nervous system and cause hypertension.....but KATZUNG has clealy mentioned that in long run maoi will cause hypotension.
I did not understand how you have tried to explain this....can you make me more clear?????
thanks
The hypertensive crises adverse effect occurs when MAOI are taken with tyramine containing food products. The most common adverse effect is POSTURAL hypotension which is minimized through divided dosage scheduling.

SONALI SEN
01-08-2007, 07:21 AM
hypertensive crisis agreed ....that is caused by taking maoi and tyramine together......IN HYPERTENSIVE CRISIS THERE IS HYPERTENSION IS'NT IT???

BUT WHY POSTURAL HYPOTENSION when MAOI is taken alone.....IS MY QUESTION?

banjul10
01-08-2007, 10:51 PM
May be something to do with changes in receptor sensitivity( i.e downregulation of Beta-adrenergic, alpha-adrenergic and serotonergic receptors) I can't think of any other mechanism that may be responsible for postural or orthostatic hypotension>

SONALI SEN
01-09-2007, 09:12 AM
I THINK banjul10 ... you are right.......may be TREVOR can give the exact answer....
thanks.

Hipp
01-10-2007, 12:51 AM
MAO inhibitors while increasing NE and serotonin at synapses block cholinergic and alpha-1 receptors. Postural hypotension is the result of alpha block and vasodialtion in venous system. blurred vision and dry mouth are their anti cholinergic consequences.

jameslynton
01-10-2007, 04:54 AM
May be something to do with changes in receptor sensitivity( i.e downregulation of Beta-adrenergic, alpha-adrenergic and serotonergic receptors) I can't think of any other mechanism that may be responsible for postural or orthostatic hypotension>I maybe wrong here from my reading - Anti depressants don't down regulate neural receptors. Only hormones (and hormone like drugs) can down regulate hormone receptors in target organs. Generally most anti depressants spare neurotransmitter depletion or effect the action potential (Li+). I am still researching this will update later.

banjul10
01-10-2007, 11:33 AM
MAO inhibitors while increasing NE and serotonin at synapses block cholinergic and alpha-1 receptors. Postural hypotension is the result of alpha block and vasodialtion in venous system. blurred vision and dry mouth are their anti cholinergic consequences.
Hipp, you are correct. however Anti-ach effect is minimal and postural hypo more common. Perhap alpha block is more pronounced.
Chronic therapy does cause downregulation of certain receptors. Similar to TCAs.







Copyright © 2003-2018 ValueMD, LLC. All rights reserved.