Drug Therapies - Anti-depressants

Question 1

What conditions are Anti-depressants prescribed for?

Answer 1

Depression (incl BPD)
Organic mood disorders
Schizoaffective disorder
Anxiety disorders e.g. OCD, panic & social phobia

Question 2

How long do anti-depressants take to work?

Answer 2

2-4wks.

The guidelines state a therapeutic trial should last atleast 2 months before you change drug

Question 3

How long after a depressive episode should someone be on prophylactic anti-depressants?

Answer 3

Depends on how many episdoes they’ve had?
1st = 6 months/1 yr
2nd = 2yrs
3rd = ~lifelong

Question 4

What are the categories of anti-depressants?

Answer 4

SSRIs - Selective Seratonin reuptake inhibitors
SNRIs - Serotonin & Noradrenaline reuptake inhibitors
TCAs - Tricyclic
MAOIs - Monoamine Oxidase inhibitors
Novel e,g, Mirtazepine & Buproprion

Question 5

In what order would we generally use anti-depressants?

Answer 5

1) SSRI
2) 2nd SSRI or augment with a novel agent
3) SNRIs
4) TCAs or MAOIs

Question 6

TCAs are very effective, why aren’t they more commonly used?

Answer 6

1st - Easy to OD
2nd - Heavy side effects:
- Antihistaminic e.g. sedation & weight gain
- Anticholinergic e.g. Dry mouth & constipation
- Antiadrenergic e.g. Orthostatic hypotension & sexual dysfunction

Question 7

What are the types of TCAs?

Answer 7

Tertiary - Worse side effects e.g. Amitryptiline

Secondary - active metabolites of tertiary

Question 8

How do MAOIs work?

Answer 8

Bind irreversible to Monoamine oxidase preventing deactivation of dopamine & serotonin

Question 9

Why don’t we use MAOIs much?

Answer 9

Side effects:

• Orthostatic HTN
• Weight gain
• Dry mouth
• Sedation
• Sleep disturbance
• HTN crisis (cheese reaction, due to tyramine)
• Serotonin syndrome => Hyperpyrexia, CV shock & death

Question 10

What are the major side effects of SSRIs?

Answer 10

GI
Sexual dysfunction (main reason patients drop out)
Acitivation syndrome
Discontinuation syndrome

Question 11

What’s Acitivation syndrome?

Answer 11

Increased serotonin from SSRIs –>:
Nausea, anxiety, panic & agitation

It only lasts 2-10 days so warn and reassure your patients

Question 12

What is discontinuation syndrome?

Answer 12

Agitation, nausea, disquilibriujm & dysphoria when stopping an SSRI

Fluoxetine has a long half life so can be used to wean off SSRIs

Question 13

What are the major SSRIs?

Answer 13

Paroxetine
Sertraline!
Fluoxetine!
Citalopram!
Escitalopram`
Fluvoxamine

Question 14

pros & cons of paroxetine?

Answer 14

Good for anxiety as it has quite a lot of sedation

Question 15

+/- for Sertraline?

Answer 15

Has relatively few side effects

Question 16

Pros of Prozac (Fluloxetine)>

Answer 16

Has a long half life so it’s good for compliance issues and preventing discontinuation syndrome

Question 17

What’s the big risk from from citalopram

Answer 17

Dose dependant QT prolongation

Question 18

How do SNRI’s work?

Answer 18

Affect both serotonin and noradrenaline reuptake, hence they work like TCAs without the big bad side effects

Question 19

List some SNRIs?

Answer 19

Venlafaxine

Duloxetine

Question 20

Pros & Cons of venlafaxine?

Answer 20

an SNRI:
Pros = g#ood renal clearance & short half life –> little toxic buildup

Cons = Dose dependant diastolic bp increase
QT prolongation
Sexual dysfunction
Bad discontinuation syndrome (due to short half life)

Question 21

Why use duloxetine over venlafaxing?

Answer 21

Less BP effect so useful in that context

Question 22

List the major 2 novel antidepressants?

Answer 22

Mirtazepine

Buproprion

Question 23

What are the risks with mirtazapine?

Answer 23

Increases serum cholesterol & Triglycerides
Weight gain & appetite increase
Sedating at low doses

Question 24

Pros and cons of Buproprion?

Answer 24

A good augmenter with few side effects. No weight gain, sexual dysfunction, sedation or cardiac problems

But increases seizure risk

Question 25

What drugs can we use to treat Resistant Depression?

Answer 25

1) Combination antidepressants e.g. SSRI/SNRI with mirtazapine
2) Adjunctive lithium
3) Adjunctive Anti-psychotic
4) ECT

Question 26

What else are SNRI’s helpful with?

Answer 26

Neuropathic pain