What is depression:Depression is a state of low mood and aversion to activity or apathy that can affect a person's thoughts, behavior, feelings, and sense of well-being.It's caused mainly by deficiency in some neurotransmitters in the brain or more specifically in the synaptic cleft like nor-epinephrine and serotonin.

At the beginning we should know how a nervous signal is transmitted through nervous cells:Nervous action potential is transmitted from the axon of one nerve cell to the dendrimers of the next nerve cell via chemical signals mediated by neurotransmitters such as nor-epinephrine, serotonin and dopamine

after doing their action by docking to receptors of the next nerve cell they undergo two processes

Overview on pharmacological management of depression

By:Ph: Abeer Abd el rahman

B.Sc of pharmacy

a) Broken down by mono amine oxidase enzymeb) Are reuptaken back into nerve cells

So the idea of treating the deficiency of nor-epinephrine and serotonin (depression) is by acting on these two mechanisms

1) The first line of treatment is mono-amine-oxidase inhibitors MAOI:

Monoamine oxidase inhibitors are drugs inhibiting the action of mono-amine-oxidase enzyme which is responsible for the breakdown of nor-epinephrine and serotonin so increase their amount and action in the synaptic cleft

Examples for available MOAI in the markets:A) Nonselective MAO-A/MAO-B inhibitors

Isocarboxazid(Marplan) Nialamide (Niamid) Phenelzine (Nardil, Nardelzine) Hydracarbazine Tranylcypromine (Parnate, Jatrosom)

B) Selective MAO-A inhibitors

o Bifemelane (Alnert, Celeport) (available in Japan)o Moclobemide (Aurorix, Manerix)o Pirlindole (Pirazidol) (available in Russia)o Toloxatone (Humoryl) (available in France)

C) Selective MAO-B inhibitors

o Rasagiline (Azilect)o Selegiline (Deprenyl, Eldepryl, Emsam, Zelapar)

Linezolid is an antibiotic drug with weak MAO-inhibiting activity.

Methylene blue, the antidote indicated for drug-induced methemoglobinemia, among a plethora of other off-label uses, is a highly potent, reversible MAO inhibitor.

Side effects of MOAI:As it increases the level of many neurotransmiiters

The most common side effects of MAOIs include:

Dry mouth Nausea, diarrhea or

constipation Headache Drowsiness Insomnia Dizziness or

lightheadedness Skin reaction at the patch site

As well as being an enzyme inhibitor it affects the metabolic capacity of liver so it decreases the metabolism of other drugs or food so used with caution and under medical supervision especially when combined with other drugs .

2) Tricyclic antidepressants (TCAs):

They act by inhibiting reuptake of nor-epinephrine and serotonin by blocking the transporters responsible for reuptake of these neurotransmitters.

This inhibition elevates the concentration of neurotransmitters in the synapses and triggers further neurotransmission. Tricyclic antidepressants are used to treat depression, bipolar disorder, anxiety, obsessive-compulsive disorder and other mood disorders. They are also effective as analgesics so are used to treat chronic pain and used for migraine prophylaxis.

Examples for tricyclic antidepressants :Asendin generic name: amoxapine Norpramin generic name: desipramine Sinequan generic name: doxepin Anafranil generic name: clomipramine Surmontil generic name: trimipramine Elavil generic name: amitriptyline Tofranil generic name: imipramine Silenor generic name: doxepin Pamelor generic name: nortriptyline Vivactil generic name: protriptyline Vanatrip generic name: amitriptyline Aventyl Hydrochloride generic name: nortriptyline

Common Side Effects:

Tricyclic antidepressants may cause a number of side effects, including:

Dry mouth Blurred vision Sweating Dizziness or lightheadedness Drowsiness Restlessness Racing heartbeat Increased sweating Urinary retention so it has off lable use in

treatment of nocturnal enuresis. Constipation Tremor Increased appetite Weight gain Low sex drive Difficulty achieving an erection, and

other sexual difficulties

3) Selective serotonin reuptake inhibitors(SSRI):Unlike TCA, SSRIs are believed to increase the extracellular level of the serotonin specifically by limiting its reabsorption into the presynaptic cell, increasing its level in the synaptic cleft and make it available to bind to the postsynaptic receptor. leading to much fewer side effects than TCA.The side effects here may be just sleeping disorders, weight gain and sexual dysfunction.

Examples for SSRIs: citalopram escitalopram fluoxetine fluvoxamine paroxetine sertraline

references

Treating depression with antidepressants by Brooke Miller https://www.youtube.com/watch?v=pGEQILM7C7Y

https://www.drugs.com/drug-class/tricyclic-antidepressants.html

http://www.mayoclinic.org/diseases-conditions/depression/in-depth/maois/art-20043992

references

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