Atypical Antidepressants - Mechanism - Indications - Adverse/side effects - antidepressant drugs -

Atypical Anti Depressants:

Atypical antidepressants have actions at several different sites. They are not SSRIs or SNRIs. They have different mechanisms of actions. They are different in the side-effect profile and have additional beneficial effects and indications. However, they are more efficacious than TCAs (tricyclic antidepressants)

Following drugs come under this category

Ø     Bupropion

Ø     Mirtazapine

Ø     Nefazodone

Ø     Trazodone

Bupropion:

It is weak dopamine and nor epinephrine reuptake inhibitor. It has a short half-life and requires more than once dosing.

The unique characteristic of Bupropion is that it reduces the craving for nicotine in individuals who wish to quit smoking.

Side effects Of Bupropion:

    Dry mouth

    Sweating

    Nervousness

    Tremor

    Increase risk of seizures at high doses

    Relatively low drug-drug interaction

    Low incidence of sexual dysfunction.

Mirtazapine:

It blocks presynaptic alpha 2 receptors and enhances the neurotransmission of serotonin and nor epinephrine.

Stimulation of alpha 2 receptors blocks further release of epinephrine or serotonin. Inhibition of alpha 2 receptors enhances the neurotransmission.

It also blocks 5 HT2 receptors. 5HT 2 receptors Inhibit neurotransmission. Therefore, inhibition of these receptors will enhance transmission.

It has antihistaminic activity and has sedative activity; hence it can be used In depressed patients having difficulty in sleeping.

Side effects of Mirtazapine:

    Increased appetite

    Weight gain

    Sedation.

Nefazodone:

This drug is a weak inhibitor of serotonin reuptake. It blocks postsynaptic 5HT 2A receptors and hence, enhances neurotransmission.

Nefazodone is hepatotoxic

Trazodone.

Its mechanism of action is similar to Nefazodone. It has been associated with priapism.