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Psychotropic Medications are prescribed for many
psychiatric disorders. Caution must be used with
these along with a lot of trust in your doctor! It is very easy to become overmedicated or get the
wrong combination of drugs so you must take it
upon yourself to do your own research and educate
yourself on what you are putting into your
precious body. To my knowledge, there has not been
any extensive research on the long-term effects
of these drugs on the body. If you know of any
research of this nature please
email me
All Depressed Brains Are Not
the Same
~About.com
Very often I am asked to recommend
a good antidepressant. My answer, other than the
obvious, "Please see your doctor for medical
advice", is this: "the one that works for you"!
Each class of antidepressant works on your brain
chemistry in a different way. Dr. Abbott Lee
Granoff, a noted expert in the field of panic
disorder and depression, says the following:
"There are currently 23 antidepressants on the
market (Guide Note: this figure is for the US
only. There are some antidepressants available in
other countries which are not approved for use in
the US-(Interesting concept (tb)).
Each increases certain
neurotransmitters in the brain and each can do
this in slightly different parts of the brain."
So, while one person may get relief from having
their serotonin boosted, another may need a drug
that affects both serotonin and norepinephrine.
Still another person may need an entirely
different sort of medication, such as an
anticonvulsant or a mood stabilizer like lithium.
Further, a person who does well on a medication
such as Zoloft may not do as well on Prozac, even
though both belong to the same class. Each person
will be very different in their medication needs.
Just like the wide variety of brains, there are a
wide variety of antidepressants. Broadly speaking,
these fall into the following classes: monoamine
oxidase inhibitors (MAOIs), tricyclics (TCAs) and
selective serotonin reuptake inhibitors (SSRIs).
There are also several newer medications that are
unique in their mechanism of action.
Monoamine Oxidase
Inhibitors
The monoamine oxidase inhibitors
(MAOIs) were some of the first antidepressant
medications developed. The neurotransmitters
responsible for mood, primarily norepinephrine and
serotonin, are also known as monoamines. Monoamine
oxidase is an enzyme which breaks these substances
down. Monoamine oxidase inhibitors, as the name
implies, inhibits this enzyme, thus allowing a
greater supply of these chemicals to remain
available.
Too Many Side Effects
MAOIs have fallen out of favor as
first-line antidepressants because they offer
several disadvantages to patients compared to
newer medications. Potentially fatal drug
interactions can occur with MAOIs when combined
with a variety of drugs which are serotonin
agonists (the "serotonin syndrome") or
norepinephrine agonists. People on these
medications must also follow strict dietary
restrictions of foods rich in tyramine to avoid
potential hypertensive (high blood pressure)
crisis. A major adverse effect that occurs on
MAOIs alone is hypotension (low blood pressure),
which can present as fatigue and may mimic
worsening of the underlying depressive syndrome.
For this reason, the blood pressure should always
be monitored when using these antidepressants.
Tricyclics
Tricyclics, also known as
heterocyclics, came into broad use in the 1950's.
These drugs inhibit the nerve cell's ability to
reuptake serotonin and norepinephrine, thus
allowing a greater amount of these two substances
to be available for use by nerve cells.
In addition to acting on norepinephrine and
serotonin, tricyclics exhibit similar effects on
histamine and acetylcholine. This is responsible
for the troublesome side-effects we usually
associate with these medications, such as dry
mouth, blurry vision, weight gain and sedation.
With tricyclics, a patient's medical history must
be closely considered. These medications may cause
orthostatic hypotension (dizziness upon standing);
rapid heartbeat, sometimes with palpitations; and
may aggravate preexisting heart conditions.
Patients with a history of seizures or head injury
must also be cautious as these drugs may cause
seizure.
Selective Serotonin
Reuptake Inhibitors
Claims of decreased side-effects
and increased safety relative to the older
medications have made this class of antidepressant
very popular in recent years. Five drugs currently
belong to this class: fluoxetine (Prozac),
citalopram (Celexa), fluvoxamine (Luvox),
sertraline (Zoloft), and paroxetine (Paxil).
SSRI stands for Selective Serotonin Reuptake
Inhibitor. These medications work, as the name
implies, by blocking the presynaptic serotonin
transporter receptor. This drug differs from the
tricyclics in that it's action is specific to
serotonin only. It's effect on norepinephrine is
indirect, through the fact that falling serotonin
"permits" norepinephrine to fall so preserving
serotonin preserves norepinephrine.
SSRIs, through their specificity,
have the advantage of not affecting histamine and
acetylcholine. The implication is that although
they are not without side-effects, they do not
create the same bothersome side-effects as the
tricyclics.
Newer Mechanisms
Five newer medications which do not
fit into the above categories are: buproprion
(Wellbutrin), nefazodone (Serzone), trazodone
(Desyrel), venlafaxine (Effexor), and mirtazapine
(Remeron).
Wellbutrin
The mechanism of bupropion's
antidepressant activity is poorly understood, but
is thought to be mediated through noradrenergic or
dopaminergic pathways or both.This medication
lacks the sexual side-effects so common to the
SSRIs and is popular for patients who exhibit a
lack of energy, psychomotor slowness and excessive
sleep.
Serzone
Nefazodone and it's precursor
trazodone both
inhibit neuronal reuptake of serotonin and, to a
lesser extent, norepinepherine. They also blocks
postsynaptic 5-HT2 receptors. Nefazodone has weak
affinity for cholinergic and adrenergic receptors
and, therefore, is associated with less sedation
and orthostasis than trazodone.
Effexor
Venlafaxine is a compound that is
structurally unrelated to other antidepressants.
Like the TCAs, venlafaxine inhibits the neuronal
uptake of both serotonin and norepinepherine.
Venlafaxine has dose-dependent, sequential effects
on the uptake pumps for serotonin and then
norepinephrine.. At 75 mg/day, venlafaxine is
predominantly a serotonin reuptake inhibitor (SRI)
like the SSRIs. At 375 mg/day, it produces
comparable norepinephrine uptake inhibition to an
NSRI such as desipramine.
Remeron
Mirtazapine is the most recently
released of these four and is the first antagonist
marketed as an antidepressant. Mirtazapine's
unique mechanism of action does not involve enzyme
inhibition or blockade of neurotransmitter
reuptake. Mirtazapine increases the release of
norepinepherine from central noradrenergic neurons
by blocking the presynaptic inhibitory alpha-2
autoreceptors. It spares the alpha-1 postsynaptic
receptor and therefore results in net increase
noradrenergic transmission. As a second
presynaptic receptor blocking function,
mirtazapine blocks the inhibitory alpha-2
heteroreceptors located on serotonergic neurons,
resulting in increase release of serotonin.
Postsynaptically, mirtazapine has low affinity for
the 5-HT1A receptor, thus allowing serotonin
released into the synapse to bind to and stimulate
this receptor. However, it blocks postsynaptic
5-HT2 and 5-HT3 receptors. Stimulation of the
5-HT2 receptor is thought to be responsible for
the serotonergic side effects of insomnia,
agitation, and sexual dysfunction seen with the
SSRI's and 5-HT3 receptor stimulation is thought
to mediate nausea seen with these agents.
Therefore, mirtazapine's receptor blocking profile
prevents the side-effects seen with nonselective
activation of serotonin receptors which occurs
with pure reuptake blockers.
A word from the author...I have
been on 7 of these medications (in addition to
others) for depression over the last several
years...what does this tell you? I am no longer on
any medication and am thriving very nicely.
If you are feeling suicidal please call
1-800-784-2433 |
