Antidepressant drugs

Question 1

What are the different types of antidepressant drugs?

Answer 1

Tricyclic antidepressants (TCAs)
Monamine oxidase inhibitors (MAOIs)
Selective 5-HT reuptake inhibitors (SSRIs)
Lithium
ECT

Question 2

What are the symptoms of depression?

Answer 2

Emotional:
Misery, apathy and pessimism 
Low self-esteem
Loss of motivation
Anhedonia 
Biological:
Slowing of thought and action
Loss of libido 
Loss of appetite
Sleep disturbance

Question 3

What is unipolar depression/depressive disorder?

Answer 3

Mood swings in same direction
Relatively late onset
Drug treamtnet

Question 4

What is reactive depression?

Answer 4

Depression in result to stressful life events- non-familial

Question 5

What is endogenous depression?

Answer 5

Unrelated to external stresses

Familial pattern

Question 6

What is bipolar depression/manic depression?

Answer 6

Oscillating depression/mania
Less common- early adult onset
Strong hereditary tendency
Drug treatment- lithium

Question 7

What is the monoamine theory of depression?

Answer 7

Depression- functional deficit of central MA transmission
Mania- functional excess of NA and 5-HT
Based on pharmacological evidence
Biochemical evidence inconsistent
Delayed onset of clinical effect of drugs
Down regulation: alpha2, beta, 5HT receptors

Question 8

What is the mechanism of action of TCA’s?

Answer 8

They are neuronal monoamine re-uptake inhibitors
Also have actions on alpha2, mAchRs, histamine and 5-HT receptors
Delayed down regulation of beta-adrenoceptors and 5-HT2 receptors

Question 9

What are the pharmacokinetics of TCAs like?

Answer 9

Rapid oral absorption
Highly PPB
Hepatic metabolism- active metabolites- renal excretion (glucuronide conjugates)
Plasma t1/2- 10-20 hours)

Question 10

What are the unwanted effects of TCAs at therapeutic levels?

Answer 10

Atropine like effects
Postural hypotension
Sedation

Question 11

What will happen if someone overdoses on TCAs?

Answer 11

CNS: Excitement, delirium, seizures, coma, respiratory depression
CVS: Cardiac dysrhythmias, ventricular fibrillation/sudden death

Question 12

What interactions do TCAs have with other drugs?

Answer 12

Many
PPB:TCA effects
Hepatic microsomal enzymes: TCA effects (neuroleptics, oral contraceptives)
Potentiation of CNS depressants (alcohol)
Antihypertensive drugs (monitor closely)

Question 13

What are the two forms of MAOI?

Answer 13

MAO-A: NA and 5-HT

MAO-B: DA

Question 14

How selective are most MAOIs?

Answer 14

Fairly non-selective

Question 15

How do MAOIs have an effect?

Answer 15

They cause irreversible inhibition (long duration of action)
Rapid effects: Cytoplasmic NA and 5-HT
Delays effects: Clinical response- down regulation of beta-adrenoceptors and 5-HT2 receptors

Question 16

What are the pharmacokinetics of MAOIs like?

Answer 16

Rapid oral absorption
Short plasma t1/2 but longer d.o.a
Metabolised in liver and excreted in urine

Question 17

What are the unwanted effects of MAOIs including droog interactions?

Answer 17

Atropine like effects
Postural hypotension
Sedation
Weight gain
Hepatotoxicity 
Drug interactions
Cheese reaction- tyramine containing foods and MAOI -> Hypertensive crisis (headache, b.p, intracranial haemorrhage)
MAOIs and TCAs-> Hypertensive episodes
MAOIs and pethidine -> Hyperpyrexia, restlessness, coma and hypotension

Question 18

What is the mechanism of action of SSRIs?

Answer 18

Selective 5-HT re-uptake inhibition

Question 19

What are the side effects for SSRIs like?

Answer 19

Less troublesome (but less affective against severe depression

Question 20

What are the pharmacokinetics of SSRIs like?

Answer 20

p.o. administration
Plasma t1/2- 18-24 hours
Delayed onset of action- 2-4 weeks

Question 21

What are the unwanted effects of SSRIs?

Answer 21

Nausea, diarrhoea, insomnia and loss of libido
Interact with MAOIs
Increase in suicidality

Question 22

What is currently the most prescribed antidepressant drug?

Answer 22

Fluoxetine (prozac)- SSRI

Question 23

What is venlafaxine?

Answer 23

Dose-dependent reuptake inhibitor
5HT -> NA -> DA
2nd line treatment for severe depression

Question 24

What is mertazapine?

Answer 24

Alpha 2 receptor antagonist
Increased NA and 5HT release
Other R interactions (sedative)
Useful in SSRI intolerant patients