Posted by dennison on April 1, 2002, at 15:40:40
In reply to Kramer (or anyone) why do side effects start first, posted by BlueJay Bird on April 1, 2002, at 14:43:09
HI Sideffects start first because the sideeffects are moreso contingent on properties inherent in drug molecule - antihistamine blockade for instance- drowsiness--- anti muscarinic effect - memory impairment - dry mouth etc -- these are more common of tricyclics off course ...................................................................... Ssri side-effects typically reflect serotonin on gastro intestinal tract -nausea etc. --( initial anxiety fro,etc. serotonin stimulation of still sensitive serotonin post synaptic receptors.
Ssri blockade of serotonin reuptake occurs extremely fast within hrs - thus this initial overload in synapse still has exposure to normal or perhaps over sensitive serotonin post synaptic receptors. ....................................These side effects reflect acute manifestations of the drug and consequent synapse "concentration being much more sustained " ...................................Therapeutic effects - "antidepressive effect" or "anxiety effect",itself comes along latter as it's neuronal plasticity, ""the bodies adaptative mechanism " trying to adjust to the initial over abundance that constitutes the "actual" longer term beneficial effect - namely down regulation of over sensitive receptors but increased serotonin transmission nonetheless through - down regulating the "pre" synaptic (( auto-receptor)) , which might in a sense be referred to as the feedback "off" switch turning down serotonin or norepinephrine release and synthesis . Gene induction, of post synaptic receptor modifications and down stream transmitting mechanisms which takes some time to come about, is significant adaptation also, but is slow in a relevant sense compared to initial acute drug effect.. ........................Thus all this adapting and eventually -re-establishing of enhanced neurotransmitter functionality takes over a period of considerable time -"thus the time lag" sometimes several weeks , while side-effects happen many times from very first dose:( .........................................................Btw --many think ssri's inc. "serotonin" or in case of tricyclics "norepinephrine and serotonin" is inc. in amount in brain, actually there is less - it's just since it remains in synapse longer due to blockade of reuptake thus "removal from synapse" -- is blocked " that the effect is more pronounced and sustained. The actual production of the neurotransmitter " aka turnover" is less , less is produced but effect is more :):). Because more transmitter is available to stimulate "post" synaptic receptors - thus bring about a behavior response !!!!!! Course it's the end result of behavior response which is wanted obviously-- otherwise --((((why bother))) :):)...
poster:dennison
thread:101317
URL: http://www.dr-bob.org/babble/20020327/msgs/101327.html