DEPRESSION: SSRIs (new)

Question 1

Why are SSRIs first line in depression?

Answer 1

• Better tolerated
• Safer in overdose

Question 2

Benefit of SSRIs over TCAs

Answer 2

o less cardiotoxic
o less sedating
o less antimuscarinic than TCAs
o SSRis safer in unstable angina and myocardial infarction and in overdose

Question 3

MoA

Answer 3

Selectively inhibit the reuptake of 5-HT from the synaptic cleft

Question 4

Commonly used SSRIs

Answer 4

Sertraline
Fluoxetine
citalopram
escitalopram
fluvoxamine

Question 5

Which antidepressant in licensed for children?

Answer 5

Under 17
Fluoxetine

Question 6

Side effects - SSRIs

Answer 6

• GI
• Hyponatraemia
• QT prolongation
• Suicidal tendencies
• Seizures
• SS

Question 7

Which SSRI have increased risk of QT prolongation

Answer 7

• Citalopram
• Escitalopram

Question 8

CI

Answer 8

• Mania
• Poorly controlled epilepsy
• Hx bleeding disorders
• Elderly
• Young (increased risk of suicidal ideation)

Question 10

Interactions

Answer 10

• CYP enzyme inhibitors (Avoid grapefruit, increases plasma conc)
• CYP enzyme inducers e.g. St John’s Wart (reducers effectiveness)
• Anticoagulants e.g. warfarin (ncreased bleeding risk)
• Aspirin + NSAIDs (give PPI)
• PPI (Omeprazole + citalopram interaction)
• APs (QT)
• Drugs that lower Na (carbamazepine, diuretics)
• MAOI (phenelzine, moclobamide) = SS

Question 11

Interactions - increased plasma concentrations

Answer 11

Grapefruit juice (enzyme inhibitor)

Question 12

Interactions - increased risk of bleeding

Answer 12

NSAIDs/Aspirin (GI bleeding)
Anticoagulant
Antiplatelets e.g. warfarin

Question 13

Interactions - increased risk of QT prolongations

Answer 13

Erythromycin (macrolides)
TCAs
Sotalol
Amiodarone
Chloroquine
Mefloquine
Lithium
Quinine
Antipyschotics

Question 14

Interactions - increased risk of QT prolongation due to hypokalaemia

Answer 14

These cause hypokalaemia, which in turn can lead to QT prolongation increases risk of TDP
* Theophylline
* Beta 2 agonists
* Loop/thiazide diuretics
* Corticosteroids

Question 15

What are the signs of hyponatraemia? and What are below what level of sodium is considered hyponatraemia?

Answer 15

• Signs include drowsiness, confusion, or convulsions
• More common in the elderly population
• Serum sodium less than 130
  mmol/L

Question 16

Interactions - increased risk of serotonergic effects/serotonin syndrome

Answer 16

St. Johns wort (serotonergic antidepressant)
Amfetamines
Sumatriptan (5-HT1a agonist)
Selegiline (MAO-B inhibitor)
Tramadol (opioid that also inhibits reuptake of 5-HT + NA)
TCAs/MAOIs (serotonergic drugs)
Ondansetron (5-HT3 antagonists)

Question 17

Which SSRI is safe in stable angina + MI

Answer 17

Sertraline

Question 18

Which SSRI has higher risk of withdrawal reactions?

Answer 18

Paroxetine

Question 19

Which SSRI is an inhibitor of CYP P450 enzymes?

Answer 19

Fluoxetine

Question 20

Fluoxetine +
Carbamazepine, Is this combination safe?

Answer 20

• SSRIs can reduce seizure threshold
• Combination can increase risk of hyponatraemia
• Plasma concentration of carbamazepine is increased by fluoxetine (although BNF does not state this)
  All these must be considered and monitored

Question 21

Overdose (poisoning)

Answer 21

N + V
Agitation
Tremor
Nystagmus
Drowsiness
Sinus tachycardia

Question 22

Abrupt withdrawal side effects

Answer 22

• Gastrointestinal upset
• Neurological (headache, dizziness, electric shock sensation)
• Sleep disturbances
• Influenza-like symptoms