Antidepressants

Question 1

Describe Mechanism of action of antidepressants generally

Answer 1

1. Inc brain biogenic amines
2. Downregulation of beta & 5-HT2 receptors (delayed 2-4 weeks)
3. Affect neurotrophic factors essential for survival & function of neurons

Question 2

Mention amine pump inhibitor antidepressants

Answer 2

TCA: imipramine, amitriptyline, clomipramine
SSRI: Fluoxetine
NDRI: Bupropion
SNRI: venlafaxine, duloxetine

Question 3

Describe mechanism of mirtazapine

Answer 3

Inc NA & 5-HT release into synaptic cleft by preventing alpha2 autoinhibition

Question 4

Mention adverse effects of TCA

Answer 4

1. Autonomic blockade (a, H1, M)
2. Inc body weight
3. Cariotoxic (conduction defects & arrhythmias) & convulsions
4. Sexual dysfunction, swiych to mania, serious drug interactions, low safety margin

Question 5

Mention adv & disadv of following:
1. SSRI
2. Bupropion

Answer 5

1. A, less cardiotoxic, no autonomic side effects, safer in overdose. D, ser syndrome esp w MAOI, nausea, anxiety, insomnia, tremors, sexual dysfunction, suicidal tendency.
2. A, No sexual dysfunction, inc NE/DA thus dec craving & used in smoking cessation. D, inc risk of convulsions

Question 6

Mention adv & disadv of following:
1. Venlafaxine
2. Mirtazapine

Answer 6

1. A, No autonomic side effects. D, nausea, sexual dysfunction, dry mouth, HTN
2. A, less nausea & sexual dysfunction. D, H1 action & antiemetic effect (5HT3 in CTZ)

Question 7

Mention drug interactions of TCA

Answer 7

1. Alcohol, anesthetics —sedation
2. Hypotensive drugs (inc postural hypotensive effects of TCAs)
3. TCA potentiate directly acting sympathomimetics (dec uptake of biogenic amines)
4. Avoid comb w MAOI (5HT syndrome)

Question 8

Describe TCA toxicity & management

Answer 8

Atropine toxicity, convulsions, conduction block & arrhythmia, hypotension
M, NaHCO3 for hypotension & arrhythmia

Question 9

Mention results of combining MAOI with the following
1. Tyramine
2. Cold remedies
3. TCA
4. SSRI

Answer 9

1&2 hypertensive crisis
3. Hypertension, convulsions, hyperthermia
4. Serotonin syndrome, convulsions, hyperthermia

Question 10

GR: MAOI should be avoided in elderly

Answer 10

Postural hypotension & atropine-like action

Question 11

GR: Moclobemide is best preferred MAOI

Answer 11

Selective on A, allows MAOB to metabolize tyramine
Short-reversible MAOA inhibitor, easily displaced by tyramine

Question 12

Describe adv & dis of agomelatine

Answer 12

A, inc release of NE via 5HT2C antagonism causing arousal, used in major depressive disorder in non-responders or intolerant to SSRI, corrects disturbances in sleep disturbance.
D, hepatotoxic

Question 13

Mention therapeutic uses of antidepressants

Answer 13

1. Major depressive disorder
2. Anxiety disorders (SSRI, clomipramine)
3. PTSD
4. Pain disorders, neuropathic pain (amitriptyline, TCA & SNRI)
5. Urinary incontinence (duloxetine), nocturnal enuresis (imipramine)
6. Eating disorders (SSRI & TCA)
7. Smoking cessation (bupropion)

Question 14

Following remission, treatmentvis continued for….., then withdrawn over…..

Answer 14

6 months
4 weeks

Question 15

Describe cases in which MAOI can be used

Answer 15

Atypical depression with obsessions, anxiety, phobias, panic attacks, 2nd choice in refractory major depression

Question 16

Mention add-on drugs in resistant cases

Answer 16

Atypical Antipsychotics, T3, lithium

Question 17

………are potent enzyme inhibitors

Answer 17

Fluoxetine & paroxetine