Lecture 76: Antidepressants Flashcards
MAOIs (key, 3)
Phenelzine, tranylcypromine, selegiline
What is special about selegline?
Patch delivery
Are MAOIs first line? What population might they be used?
No–after trying other anti-depressants first; atypical depression: sleep/eat a lot
MAOI mechanism
MAO located in presynaptic neuron and degrades monoamines –> MAOIs inhibit enzyme, inhibiting degradation of monoamines
Important MAOI mechanism notes
More NT in both presynaptic neuron AND cleft; irreversible (MAOIs take 2 weeks to recover)
Describe types of MAOs and targeted catecholamines. Which one is in the gut? Which one degrades tyramine? Which are targeted by MAOIs?
MAOa: 5-HT, NE, Epi, DA; MAOb: DA; MAOa; both; both
2 MAIN (scary) side effects of MAOI and mechanism
- Also inhibit breakdown of Tyramine –> NE release (hypertensive crisis) if combined with tyramine diet or adrenergic agonists; 2. Serotonin syndrome if combined with other serotonergic drugs
Other SEs of MAOIs (5)
Orthostatic hypotension, weight gain, insomnia, sexual dysfunction, rare hepatoxicity
Describe symptoms serotonin syndrome (11)
Abdominal pain, diarrhea, sweating, hyperthermia, tachycardia, hypertension, myoclonus, tremor, irritability, delirium, death
What can you NOT take with MAOIs because of serotonin syndrome (3)
Other antidepressants, dextromethorphan (cough medicine) and opiates
What else can you NOT take with MAOIs? Why?
Decongestants, stimulants because they can cause hypertensive crisis (BP > 120 mm Hg) due adrenergic agonists
What food items must be avoided with MAOIs? Why?
Tyramine inhibition in GUT via MAOa but if tyramine gets access to NE sympa neurons, these MAOa are ALSO blocked leading to NE release; soy, beer, red wine, aged cheese, dried sausage, liver, smoked fish, sauerkraut
How long must a patient wait to resume normal diet after stopping MAOI?
2 weeks
Describe Selegiline’s hope
At low doses only inhibits MAOb, but turns out at antidepressant levels, also inhibits MAOa so STILL requires dietary restriction
TCAs (key, 1) and secondary amines (key, 2)
Amitriptyine; nortriptyline, desipramine
Mechanism of TCAs (?)
Inhibit re-uptake of NE and 5-HT
TCA therapeutic uses (4)
Depression, neuropathic pain, anixety, migraine
How are tertiary amines different?
Also inhibit 5-HT reuptake
TCA SEs via receptor
H1 blocker: sedation, weight gain; Alpha1 blockers: orthostatic hypotension; M1 blocker (anticholinergic) constipation/urinary retention, dry mouth, blurred vision; Na channel blockers: type 1 antiarrythmic effects; Serotonin Reuptake inhibitors (same as SSRIs)