120: Antidepressants

Question 1

Which classes of antidepressants are useful in the treatment of chronic pain?

Answer 1

SNRIs (serotonin-norepinephrine reuptake inhibitors)

TCAs

Question 2

Which class of antidepressants is especially useful for treating migraine?

Answer 2

TCAs

(Especially amitryptiline)

Question 3

Which amino acid is a precursor for serotonin?

Answer 3

Tryptophan

Question 4

Tyrosine is a precursor for which neurotransmitters?

Answer 4

Dopamine, NE

(Dopamine is a precursor for NE)

Question 5

List 3 common features of all classes of antidepressants

Answer 5

• Takes 3-8 weeks to be maximally effective
• All have equivalant response and remission rates
  
  • 50-70% response
  • 35-50% remission
• Placebo-drug differences depend on the level of severity of depression
  
  • More severe depression = less placebo effect

Question 6

If a patient experiences partial improvement at the maximally tolderated dose of antidepressant A, what is the next step in their management?

Answer 6

Add another antidepressant of a different class

OR

Target residual symptoms with other treatments

Remeber: The goal of treatment is complete response

Question 7

Answer 7

c. Bupropion

• Helpful in depression w/o anxiety symptoms
• Will treat comorbid tobacco dependence

Question 9

How should you select a first-line antidepressant?

(What factors should influence your decision?)

Answer 9

• Side effect profile
• Past response
• Comorbid medical and psichiatric problems

Remember: no significant differences in efficacy among first line medications

Consider psychotherapy in addition

Question 10

Which classes of antidepressants are first line for treating depression?

Answer 10

• SSRI
• SNRI
• Mirtazapine
• Bupropion

Select agent based on side-effect profile

All have comparable efficacy

TCAs and MAOIs are not first line due to higher side effect burden, potential for lethal overdose

Question 11

What are the 6 most common side effects of SSRIs and SNRIs?

Which ones usually improve?

Answer 11

• GI upset
• Anxiety, agitation
• Insomnia
• Headache
• Sweating
• Sexual dysfunction

All except sexual dysfunction usually improve

Question 12

List 3 serious risks of antidepressant treatment

Answer 12

• Increased risk of suicidal thinking, behavior in young people
  
  • Highest in the first few days on the medication
  • Risk of treatment < risk of untreated depression
• Serotonin syndrome
• Do not give antidepressant monotherapy for anyone with bipolar disorder
  
  • Increases manic episodes

Question 13

What is serotonin syndrome?

How can it be avoided?

Answer 13

Result of increased 5HT activity in the brain, usually from multiple serotoninergic drugs

• Mental status change
• Hyperthermia
• Hyperreflexivity

Never combine MAOIs with TCAs or SSRIs

Question 14

Which SSRI has the longest half life?

Why is this important?

Answer 14

Fluoxetine

• No need to taper
• Requires long wash-out if transitioning to MAOI

Question 15

Which SSRI has the highest risk of drug-drug interactions?

Why?

Answer 15

Paroxetine

It is a potent CYP26 inhibitor

Question 16

Which SSRI has the shortest half life?

Why is this important?

Answer 16

Paroxetine

Results in the worst discontinuation symptoms (must taper)

Question 17

Which SSRI should be avoided in anyone with cardiac comorbidities?

Answer 17

Citalopram

Dose-depenent QT prolongation

Question 18

Which SSRI is preferred in pregnancy?

Answer 18

Sertraline

Question 19

What is the most common side effect of the SNRIs?

Answer 19

Hypertension

(In addition to the side effects common to all agents that increase 5HT and NE: GI upset, weight gain, sweating, sexual dysfunction)

Question 20

What is the mechanism of action of TCAs?

Answer 20

Inhibit NE and 5HT reuptake

Question 21

What are the common side effects of TCAs?

Answer 21

• Sedation
• Weight gain
• Orthostatic hypotension
• Arrhythmia (may be fatal)
• Seizure
• Sexual dysfunction
• Anticholinergic effects
  
  • Dry mouth, urinary retention, constipation

Question 22

What special diet must be followed when a patient is on a MAOI?

What happens if they do not follow this diet?

Answer 22

Tyramine free diet:

No aged cheese, red wine, fava beans, cured meats

Can cause hypertensive crisis if ingested while on MAOI

Question 23

Which antidepressant should you prescribe to a patient that does not have anxiety symptoms and does not want to experience weight gain or sexual dysfunction?

Answer 23

Buproprion

May worsening existing anxiety symptoms

(Mirtazapine does not have sexual side effects, but can cause weight gain)

Question 24

Which antidepressants carry the lowest risk of switch to mania if there is undiagnosed bipolar disorder?

Answer 24

Bupropion

Mirtazapine

Question 25

What are the mechanisms of action of mirtazapine?

Answer 25

• blocks
  
  • Alpha-2
  • 5HT-2 and 5HT-3
  • H1
• Increased NE and 5HT release

Question 26

Which antidepressant is often used elderly patients with insomnia and low appetite?

Answer 26

Mirtazapine

Side effects of sedation and weight gain may be helpful!

Question 27

What is the mechanism of trazodone?

Answer 27

• 5HT-2 receptor block
• Alpha-1 block
• Histamine block

(Not great for depression, effective for insomnia)

Question 28

Which antidepressant has the potential side effect of priapism?

Answer 28

Trazodone