L3- Antidepressants (MAOIs)

Question 1

list the MAOIs

Answer 1

Isocarboxazid
Phenelzine
Tranylcypromine
Selegiline

Question 2

describe the functions of the different MAOs

Answer 2

(monoamine oxidase)

• MAO-A: preferentially metabolizes NE, 5-HT
• MAO-B: metabolizes Dopa, tyramine

Question 3

MAOIs mostly correlates with its inhibition on MAO-(A/B)

Answer 3

MAO-A, which has preferential metabolism foe NE, 5-HT

MAO- B is for Dopa, tyramine; less correlation with depression, but important for AEs

Question 4

group the MAOIs

Answer 4

Hydrazine derivatives: isocarboxazid, phenelzine

Non-hydrazines: tranylcypromine, selegiline

Question 5

list the main AEs of MAOIs

Answer 5

• drowsiness, insomnia
• nausea
• orthostatic hypotension
• weight gain
• muscle pain
• sexual dysfunction

Question 6

what are the serious drug interactions with MAOIs

Answer 6

• serotonin syndrome (excess serotonin)

- cheese reaction (w/ tyramine intake in certain foods)

Question 7

Serotonin Syndrome:

• (1) Sxs
• (2) management

Answer 7

1- hyperthermia, muscle rigidity, myoclonus (jerky contractions of muscle group)

2:

• discontinue meds
• supportive care
• benzodiazepines (sedation)
• cyproheptadine (5-HT antagonist)

Question 8

Serotonin Syndrome:

• results from overstimulation of (1)
• (2) is the most common combination leading to serotonin syndrome

Answer 8

1- 5-HT1A, 5-HT2 receptors

2- irreversible MAOI with serotogenic agent (but can occur with drug or combination that inc 5-HT)

Question 9

_______ is the 5-HT antagonist

Answer 9

cyproheptadine

Question 10

Cheese Reaction:

• (1) mechanism
• (2) Sxs
• (3) management

Answer 10

1- ingested tyramine not degraded in gut via MAO-B –> catecholamine release

2- HTN, tachycardia, arrhythmias, seizures, possibly stroke

3- phentolamine (non-selective α antagonist) or prazosin (α1 inverse agonist) –> to reverse hypertensive crisis

Question 11

describe the alternate mechanisms of the cheese reactions

Answer 11

(not tyramine ingestion)

• sympathomimetic drugs + MAOI => HTN
• OTC cold med w/ pseudoephedrine / phenylpropanolamine are contraindicated

Question 12

_______ MAOI has the lowest risk for the cheese reaction, explain

Answer 12

selegiline: can be administered by transdermal patch, therefore has a slower release of drug

Question 13

list some foods rich in tyramine

Answer 13

(cheese reaction)

• aged cheese
• chicken liver
• soy products
• pickled fish
• red wine