MAOIs

Question 1

MoA

Answer 1

Blocks monoamine oxidase enzymes, which leads to an accumulation of monoamines:
- DA
- NA
- 5HT

Question 2

When are they used?

Answer 2

Rarely used due to significant food/drug interactions.

Question 3

Irreversible MAO-A & MAO-B inhibitors

Answer 3

• Phenelzine (hepatotoxicity more likely)
• Isocarboxazid (hepatotoxicity more likely)
• Tranylcypromine (greatest stimulant action)

Question 4

Reversible MAO-A inhibitors

Answer 4

Moclobemide
- No washout period
- Short acting

Question 5

Side effects

Answer 5

• Hepatotoxicity
• Postural hypotension/hypertensive responses
• Hypertensive crises (tranylcypromine)

Question 6

Hepatotoxicity

Answer 6

More likely with phenelzine and isocarboxazid

Question 7

Postural hypotension/hypertensive responses

Answer 7

Discontinue if palpitations or frequent headaches occur

Question 8

Hypertensive crises (tranylcypromine)

Answer 8

Discontinue if hypertensive crises with throbbing headaches.
More likely with tranylcypromine - most stimulant action

Question 9

Patient counselling

Answer 9

Avoid foods containing tyramine
Fresh food only - avoid stale/going off food.
Avoid alcohol/low alcohol drinks.
Dangers of food/drug interactions exist two weeks after stopping an irreversible MAOI

Question 10

Interactions - hypertensive crises

Answer 10

Sympathomimetics
- Pseudoephedrine
- Adrenaline
- Noradrenaline

Dopaminergic drugs
- Levodopa
- DRAs
- MAOB inhibitors

TCAs (potentially lethal)
ESPECIALLY
- Tranylcypromine
- Clomipramine