Antidepressants

Question 1

Mechanism of SSRI

Answer 1

1. 5HT1A centrally 
• Relief of depression
• Anxiolytic effect
2. 5HT2A in spinal
cord
• Sexual dysfunction:
delayed ejaculation,
anorgasmia, decreased
interest/libido
3. 5HT2C/5HT2A
in brain
• Activation: anxiety,
insomnia
• Worst with fluoxetine,
paroxetine
• Warn patients anxiety
may worsen in first 1-2 wk of treatment
4. 5HT3A in gut 
• GI upset: nausea,
vomiting, bloating
• Take with food

Question 2

Treatment strategies for refractory depression

Answer 2

1. Start with SSRI/SNRI/Mirtazepine
2. Reassess every 1-2 weeks for 3-4 weeks
   a. Full response->continue
   b. No or partial->optimise, reassess every 4-8 weeks
3. If partial response->combine, augment
4. If no response->switch

Question 3

Pharmacological approach, changing drugs

Answer 3

1. Optimisation of dose
2. Augmentation->with drug not an antidepressant (thyroid, lithium, atypical)
3. Combination
4. Substitute

Question 4

First line and second line

Answer 4

1. SSRI/SNRI/Mirtazepine

2. TCA, mianserin, MAOI

Question 5

Side effects

Answer 5

1. Agitation
2. GIT: nausea, anorexia, diarrhea, discomfort
3. Insomnia
4. Hypertension
5. Orthostatic hypotension
6. Sedation
7. Sexual dysfunction->decreased libido, anorgasmia, ejaculatory disturbance
8. Weight gain
9. Bleeding
10. Hyponatremia
11. Serotonin toxicity

Question 6

Most sedating->option if insomnia

Answer 6

Mirtazepine, take at night

Also fewer sexual dysfunction

Question 7

Avoid in liver impairment

Answer 7

Duloxetine

Question 8

Avoid in evening because of insomnia

Answer 8

Fluoxetine

Moclobemide

Question 9

Initial weight loss

Answer 9

Fluoxetine
Fluvoxamine
Paroxetine
Sertraline

Question 10

++Orthostatic hypotension

Answer 10

Fluoxetine
Paroxetine
Sertraline
SNRIs
Moclobemide

Question 11

Risks of hyponatremia

Answer 11

Risk factors for hyponatraemia include:

older age
female gender
low body weight
concurrent drugs (eg diuretics, NSAIDs, carbamazepine, chemotherapy)
impaired renal function
comorbidity (eg hypothyroidism, diabetes, chronic obstructive pulmonary disease, hypertension, stroke, head injury)
hot weather.

Question 12

First line treatment option for depression with psychosis

Answer 12

1. ECT

Question 13

Counselling a patient on antidepressants

Answer 13

1. SSRIs are used to treat depression, to restore the balance of neurotransmitters affected in depression
2. They can take 2-4 weeks to build up effect, best to wait 3-4 weeks before deciding it doesn’t work. Can increase dose over 2-4 weeks as tolerated.
3. May experience some initial anxiety in the first 1-2 weeks, this is normal. Neurovegetative states improve first, then cognition. If you have any +agitation, restless, anxiety, see your doctor. May +suicidality in children/young people
4. Usual course is for 6 months, tablet taken every day and then tapered slowly. May be for longer.
5. 5-7 in 10 people will have good response in first few weeks. Twice as likely to improve, but not in everybody.
6. Do not stop taking the medication suddenly, do not take any more than prescribed.
7. SSRIs have similar efficacy.
8. Most common side effects include: diarrhea, nausea, vomiting and headaches.
9. Other possible are: sedation, sexual dysfunction, bleeding, change in sodium, insomnia and weight gain.
10. Not addictive but can have withdrawal symptoms if stopped abruptly: dizzy, anxiety, sleep, flu like, diarrhea, abdominal pain, parasthesia, mood swings, low mood.
11. Precautions: do not take with medicines to treat migraine, St Johns wart, alcohol
12. If you miss a dose, do not double the dose