Antidepressants

Question 1

What is the cause of depression?

Answer 1

Originally it was thought to be low levels of serotonin but is more likely to be aa reduction in serotonin receptors in the hippocampus

Question 2

Describe the mode of action of MonoAmine Oxadase Inhibitors

Answer 2

Inhibits MAO enzymes who’s function in to breakdown norepinephrine, serotonin and dopamine. Therefore inhibiting this enzyme increases levels of all three NTs

Question 3

Name some MAOIs and the side effects

Answer 3

• Phenelzine,
• Selegiline (used in Parkinson’s),
• Tranylcypromine.
  Side effects are weakness, headache, weight gain, dizziness, fatigue and impotence.

Question 4

What are the interactions of MAOIs

Answer 4

They should not be used in combination with SSRI/Tricyclic, and analgesics such as morphine/tramadol. These will increase serotonin levels to potentially dangerous levels.
Foods high in tyramine such as cheese, alcohol, meats eg, venison and some green veg - causes hypertensive crisis.

Question 5

Name a reversible MAOI (RIMA) and how it works

Answer 5

Moclobemide. It acts by reversibly inhibiting MAO type A enzymes.

Question 6

How do tricyclic antidepressants work?

Answer 6

Inhibiting the re-uptake of norepinephrine and serotonin by blocking the transporters responsible for re-uptake

Question 7

What are some of the uses of Tricyclic antidepressants?

Answer 7

Depression, Anxiety, Chronic pain, IBS, neuralgia, OCD, Nocturnal enuresis, PTSD

Question 8

What are some of the side effects of tricyclic antidepressants?

Answer 8

• Increases risk of arrhythmias,
• Reduces intestinal mobility,
• Induce bradycardia followed by tachycardia,
• reduce bronchial secretions,
• urinary retention,
• Dry mouth and confusion
• Dangerous in overdose so be careful with suicide risk!

Question 9

Name some common tricyclic antidepressants

Answer 9

• Amitriptyline,
• Clomipramine,
• Imipramine,
• Lofepramine,
• Nortriptyline.

Question 10

What is Trazodone?

Answer 10

A drug related to the class of tricyclics which has a sedating effect.

Question 11

How do selective serotonin re-uptake inhibitors work?

Answer 11

Increase the levels of serotonin by limiting re-absorption allowing for increased levels of the neurotransmitter. They have only a weak affinity for norepinephrine and dopamine so tend to have fewer side effects and are better tolerated.

Question 12

What are the serotonin receptors?

Answer 12

5-hydroxytryptamine. (5-HT)

Question 13

What are some of the uses of SSRIs?

Answer 13

• Depression
• Anxiety,
• OCD,
• Panic Disorder,
• PTSD,
• Eating Disorder

Question 14

Name some examples of neurotransmitters that the 5-HT receptor modulates the release of and what impact this have.

Answer 14

GABA, Dopamine, Adrenaline, Noradrenaline and Acetylcholine. These NTs influence aggression, anxiety, cognition, learning memory, mood and sleep.

Question 15

What are the side effects of SSRIs?

Answer 15

• Sexual dysfunction and reduced libido.
• Cardiac (citalopram can prolong the QT interval)
• Bleeding (increases risk of GI bleeding),
• Risk of suicide, especially in children and adolescents.
• Nausea,
• Rash,
• Sweating,
• Insomnia,
• Muscle aches,
• Epilepsy (may reduce seizure threshold)

Question 16

What are the most toxic SSRIs?

Answer 16

Citalopram, Escitalopram, paroxetine, sertraline and then the least toxic is fluoxetine

Question 17

Name two serotonin norepinephrine up-take inhibitor (SNRI)

Answer 17

Duloxetine and Venlafaxine

Question 18

Name a presynmaptic alpha2-adrenoreceptor antagonist, its uses and side effectes

Answer 18

Mirtazapine. Used for depression, anxiety and PTSD but low dose can cause drowsiness and high dose can have stimulating effect

Question 19

What are the uses and side effects of duloxetine

Answer 19

It is used for depression, neuropathic pain and stress urinary incontinence. Side effects include nausea, insomnia and dizziness

Question 20

What are the uses and side effects of Venlafaxine

Answer 20

Used in major depressive disorder, anxiety, panic, social phobia, and often used in resistant depression

Question 21

Name an antipsychotic which has anti-depressant properties?

Answer 21

Risperidone

Question 22

What drug is used in bipolar?

Answer 22

Lithium. Can have adverse effects in kidney and thyroid

Question 23

How are antidepressants used in pain management?

Answer 23

They have a direct effect on the mechanism of the pain. For example tricyclics work by blocking reuptake of noradrenaline and serotonin into nerve endings and increasing their levels in the pain control pathway

Question 24

Prolongation of the QT interval can lead to?

Answer 24

Life threatening arrhythmia known as torsades de pointes.

Question 25

Name some examples of drugs that can prolong the QT interval

Answer 25

Antimicrobials eg, eryhtromycin and clarithromycin. Antiarrhythmias - Amiodarone. Antipsychotics - Clozapine. Antidepressants - Citalopram or amitriptyline, Antiemetics - domperidone.