Antidepressants are medications used to treat major depressive disorder. There are four main classes of antidepressants: selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors (SNRIs), and monoamine oxidase inhibitors (MAOIs). SSRIs work by inhibiting the reuptake of serotonin, while tricyclic antidepressants inhibit the reuptake of both serotonin and norepinephrine. SNRIs also inhibit the reuptake of serotonin and norepinephrine. MAOIs work by inhibiting the monoamine oxidase enzyme. Each class of antidepressants has different side effect profiles, with SSRIs generally having fewer side effects than tricyclic

1. Antidepressants
Definition:-
Antidepressantsare medicationsusedtotreatmajordepressive disorder,
Classificationof antidepressantsdrug.
1. Selectiveserotoninreuptakeinhibitors.
2. Tricycle antidepressants.
3. Serotoninnorepinephrine reuptake inhibitors.
4. Monoamine oxidase inhibitor.
Selective serotoninreuptake inhibitor(SSRI's)
SSRI’sinclude drugslike
a. Fluoxetine
b. Fluvoxemine
c. Sertraline
d. escitalopram.
Mechanismof action.
SSRI’sblocksreuptake of serotoninfrom synapseintothe serotonergicNerveendingbyinhibitingthe
serotoninTransporter(SERT)

2. Major sideeffects of SSRI's
i. Sexual dysfunction.
ii. Serotoninsyndrome.
MildSide Effects are.
i. Nausea,
ii. VOmiting
iii. Insomnia
iv. headache
v. restlessnessand
vi. Anxiety.
Tricyclic antidepressants.
Tricyclic antidepressantsdrug like
1. Imipramine
2. desipramine
3. clomipramine
4. amitriptyline
5. nortriptyline
6. doxepin.
Mechanismof action
Tricyclicantidepressantsdrugwhichinhibitthe reuptake of norepinephrine andserotoninbothat
presynapticterminalsbybinding the serotonintransporterandnorepinephrineTransporter.
Adverse effectslike
i. Sedation
ii. confusion
iii. postural
iv. hypotension
v. tachycardia
vi. sweating
vii. anticholinergicside effects.

3. Major side effect
i. Conversation
ii. weightgain
iii. cardiac arrhythmiasand
iv. acute toxicity.
v. Respiratorydepression.
Advantagesof ssri’sover TCA.
 Low cardiovascularside effects.
 AnticholinergicSide Effectsare negligible.
 Lesssedation.
 Preferredinelderlybecauseof low anticholinergiceffects.
 SaferinOverdose.
 Due to lowside effectprofile ssrsare generallywelltoleratedand acceptedbypatient.
Serotonin Norepinephrine reuptake inhibitors(SNRI's)
1. Venlafaxine
2. Desvenlafaxine
3. Duloxetine
4. milnacipran
Mechanismof action
These drugswhichinhibitthe reuptake of serotoninandnorepinephrine.
By bindingthe SERTand NET.
SNRI's Actionand side effect are same asTCA's
Monoamino oxidase inhibitors
MAO'sare.
1. Phenelzine
2. Tranylcypromine
3. Moclobemide
 Monoamine oxidase inhibitorisanenzyme whichmetabolismnorepinephrine andserotonin
and dopamine.

4. Mechanismof action
 The drug whichinhibitthe enzyme andenhancesthe neuronal level of monoamine like
norepinephrinedopamine andserotonin.
Usesof antidepressantdrugs.
1. Endogenousdepression.
2. Panicattack.
3. Obsessive compulsivedisorder.
4. OtherAnxiety disorders.
5. Disordersof pain.
6. Psychomotordisorder.
7. Bulimianervosa.
8. Premenstrual syndrome.
9. Smokingwithdrawal.
10. Nocturnal enuresis.