Useful for postgraduates in pharmacology

1. PEDAGOGY
SSRI
DR.SUMITHA. A MBBS.,MD
PHARMACOLOGY

2. PEDAGOGY
• Pedagogy, taken as an academic discipline, is the
study of how knowledge and skills are exchanged in
an educational context, and it considers the
interactions that take place during learning

3. Selective Serotonin Reuptake
Inhibitors(SSRI)
Anti depressant drug

4. Mechanism of action
• SSRIs increase the levels of serotonin
in the synaptic cleft.
• It blocks reuptake of serotonin by inhibiting
membrane associated SERT(serotonin transporter) in
serotonergic neurons.

6. • Therapeutic lag- 2 to 3 weeks.
• SSRI treatment causes stimulation of 5-HT1 auto receptors
in the raphe nucleus: this reduces serotonin synthesis and
release toward pre-drug levels.
• With repeated treatment with SSRIs, there is a gradual
down-regulation and desensitization of these autoreceptor
mechanisms. These include sustained increases in
cyclic AMP signaling and phosphorylation of the
nuclear transcription factor CREB, as well as
increases in the expression of trophic factors such
as BDNF

7. SSRI DRUGS
• Fluoxetine
• Fluvoxamine
• Paroxetine
• Sertraline
• Citalopram
• Escitalopram
• Dapoxetine

8. Pharmacokinetics
• Orally active drugs
• Metabolised by CYP 2D6 enzymes.
• Elimination half life of drugs corresponds with once
daily dosing.
• Caution- while combining SSRI with drugs
metabolised by CYP 2D6,CYP 3A4 enzymes
(e.g.warfarin,TCAs,haloperidol)
• Excretion –Kidney.

9. USES OF SSRI DRUGS
• Endogenous depression
• Obsessive compulsive disorder
• Panic disorder
• School phobia
• Post traumatic stress disorder-Sertraline used
• Kleptomania
• Bulimia nervosa-fluoxetine,fluvoxamine used

10. Adverse effects
• Insomnia,agitation,increased anxiety- excessive
stimulation of brain 5HT2 receptors.
• Sexual dysfunction –erectile dysfunction,decreased
libido:excessive stimulation of spinal 5HT2 receptors.
• Nausea,diarrhoea,emesis:excessive stimulation of
5HT3 receptors in gut.

11. • Serotonin discontinuation syndrome
Sudden withdrawal of SSRI with shorter half life like
Paroxetine and Sertraline lead to Serotonin
discontinuation syndrome.
(paraesthesia,agitation,insomnia,bowel upset)

12. Serotonin Syndrome
Elevated levels of serotonin in synaptic cleft, when
SSRI combined with MAO I (Mono amine oxidase
inhibitors) due to reduced metabolism of
serotonin,and its inhibited uptake in to neurons.
characterised by hyperthermia,muscle
rigitidy,tremor,cardio vascular collapse.

13. SUMMARY OF SSRI
Drugs
Mechanism of action
Uses of SSRI
Adverse effects
Serotonin syndrome

14. THANK YOU