Antidepressants

Question 1

What is the likely cause of depression

Answer 1

Reduction of serotonin receptors in the hippocampus

Question 2

What are the different types of antidepressants?

Answer 2

• Mono Amine Oxidase Inhibitors
• Reversible Mono Amine Oxidase Inhibitors
• Tricyclic antidepressants
• Selective serotonin reuptake inhibitors
• Serotonin norepinephrine up take inhibitors

Question 3

What is the mechanism of Mono Amine Oxidase Inhibitors?

Answer 3

• Inhibit MAO enzymes that break down norepinephrine/ serotonin and dopamine
• Inhibiting increases the levels of all of these neurotransmitters

Question 4

Name examples of mono amine oxidase inhibitors

Answer 4

• Phenelzine
• Selegiline
• Tranycypromine

Question 5

What are the side effects of mono amine oxidase inhibitors?

Answer 5

• Weakness
• Headache
• Weight gain
• Dizziness
• Fatigue
• Impotence

Question 6

What are the interactions of mono amine oxidase inhibitors?

Answer 6

• Can cause dangerous levels of serotonin causing hypertension, confusion, tremor, coma and potentially death if used with SSRI tricyclic or some analgesics e.g. morphine or tramadol
• Need a 14 day washout period to avoid interactions
• Foods high in tyramine may cause hypertensive crisis e.g. cheese, certain meats, alcohol, some green vegetables

Question 7

Example of reversible mono amine oxidase inhibitor

Answer 7

Moclobeminde

Question 8

What are the interactions of reversible mono amine oxidase inhibitors?

Answer 8

• Tyramine has less of an effect

* Because it is a shorter acting medication can be changed with only a one week washout period

Question 9

What is the mechasnim of tricyclic antidepressants?

Answer 9

• Inhibit the reuptake of norepinephrine and serotonin by blocking transporters responsible for re-uptake
• Increases the concentration of neurotransmitters in the synapse, triggering further neurotransmission

Question 10

Name examples of tricyclic antidepressants

Answer 10

• Amitriptyline
• Clomipramine
• Imipramine
• Lofepramine
• Nortriptyline

Question 11

What are the interactions of tricyclics?

Answer 11

• May cause arrhythmia in cardiovascular disease

* Very dangerous if overdosed (caution in suicidal patient)

Question 12

What are the side effects of tricyclics?

Answer 12

• Reduced intestinal mobility
• Can induce bradycardia followed by tachycardia
• Reduce bronchial secretion
• Urinary retention
• Dry mouth
• Confusion

Question 13

Why should tricyclics be avoided in the elderly?

Answer 13

Because of the side effects causing urinary retention, dry mouth and confusion

Question 14

Trazodone

Answer 14

Related to tricyclics but more sedating

Question 15

What is the mechanism of selective serotonin re-uptake inhibitors?

Answer 15

• Limits the reuptake of serotonin, acting on the 5-hydroxytryptamine (5HT) receptor
• Only have a weak affinity for norepinephrine and dopamine transmitters so are generally better tolerated with fewer side effects

Question 16

Name examples of Selective Serotonin Re-uptake inhibitors

Answer 16

• Citalopram (most toxic)
• Escitalopram
• Paroextine
• Sertaline
• Fluoxetine (least toxic)

Question 17

What are the side effects of selective serotonin re-uptake inhibitors?

Answer 17

• Sexual dysfunction and reduced libido
• Cardiac: some (esp. citalopram) can cause QT interval prolongation
• Bleeding: affects anticoagulants (i.e. warfarin), increasing risk of GI bleeds
• Possible increased risk of suicide
• Nausea
• Rash
• Sweating
• Headaches
• Insomnia
• Muscle aches

Question 18

What are the interactions of selective serotonin reuptake inhibitors?

Answer 18

• Anticoagulants

* May reduced fit threshold in epilepsy

Question 19

What is the mechanism of Duloxetine?

Answer 19

• Serotonin norepinephrine re-uptake inhibitor

Question 20

What are the side effects of duloxetine?

Answer 20

• Nausea
• Insomnia
• Dizziness

Question 21

Mechanism of Mirtazapine?

Answer 21

• Presynaptic alpha-2 adrenoreceptor antagonist and specific serotonergic antidepressant

Question 22

What are the side effects of Mirtazapine?

Answer 22

• Low doses cause drowsiness so best taken at night

* High doses give a more stimulant effect so better taken in the morning

Question 23

Mechanism of Venlafaxine

Answer 23

Serotonin norepinephrine reuptake inhibitor

Question 24

What are the uses of venlafaxine?

Answer 24

• Major depressive disorder
• Anxiety
• Panic
• Social phobia
• Resistant depression

Question 25

Name antipsychotics

Answer 25

* Risperidone | * Lithium

Question 26

When is lithium used?

Answer 26

* Bipolar/mania mood stabilisation * Possible adverse effects on the kidney and thyroid function * Regular blood tests every 3-4 months

Question 27

Which groups of people are more at risk of QTc prolongation?

Answer 27

* Major psychiatric disorder * Cardiovascular disease * Women * The elderly