Flashcards in Lec 74 Antidepressants Deck (60)
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1
What are the classes of antidepressants?
- MAO inhibitors
- tricyclic antidepressants
- selective serotonin reuptake inhibitors
- antidepressants with multiple receptor targets
2
What is therapeutic use of MAO inhibitors?
atypical depression
anxiety
hypochondriasis
treatment resistant depression/panic disorder/social anxiety disorder
3
What is mech of action of MAO inhibitors?
- irreversibly inhibit degradation of MAOs in presynaptic terminals
- causes increase 5HT, NE, DA in presynaptic terminals and synaptic cleft
4
What are substrates of MAO-A vs MAO-B?
MAO-A: 5HT, NE, DA
MAO-B: phenylethylamine, DA [NOT 5HT, NE]
5
What is first aid mnemonic for MAO inhibitors?
MAO takes pride in shanghai
- MAO
- Tranylcypromine
- Phenelzine
- Isocarboxazid
- Selegiline
6
What are the side effects of MAO inhibitors?
serotonin syndrome if combined w/ other 5HT drugs
hypertension if combined with tyramine diet or drugs that are adrenergic agonists
orthostatic hypotension, weight gain, insomnia, sexual dysfunction, rare hepatotoxicity [for phenelzine + iso]
7
What are symptoms of serotonin syndrome?
symptoms: ab pain, diarrhea, sweating, tremor, hyperthermia, tachycardia, hypertension, myoclonus, irritability, delirium, death
8
What causes serotonin syndrome?
selected drugs in combo with MAOI
- other antidepressants
- cyclobenzapine
- carbamazepine
- dextromethorphan
- opiaties: meperidine, fentanyl, methadone
- tramadol
- st johns wort
- SSRI
9
What is a hypertensive crisis? symptoms?
defined by diastolic BP > 120
symptoms: headache, palpitations, stiff/sore neck, N/V, sweating, dilated pupils, photophobia
10
What triggers hypertensive crisis? what drugs to avoid?
triggered by noradrenergic drug + MAO inhibitor
avoid
- decongestants
- stimulants [amphetamines]
- appetite suppressants
- antidepressants with NRI [TCAs, SNRIs, buproprion]
11
What is a tyramine-induced hypertensive crisis?
- ingestion of tyramine-rich foods in presence of MAO-I can trigger hypertensive crisis
- tyramine is a catecholamine releasing agent
- intestinal wall MAO-A breaks down tyramine before absorption
- if tyramine gets access to NE sympathetic neurons --> will release NE; but don't have to worry about it because MAO-A breaks down tyramine before it gets a chance
if you inhibit MAO-A --> can't handle dietary tyramine, release NE and no MAO-A to destroy it --> increased BP
12
What foods should you avoid on MAO-I?
avoid: soy, beer, red wine, aged cheese, dried sausage, fava beans, liver, smoked fish, sauerkraut
continue diet for 2 wks after stopping MAO-I to allow re-synthesis of MAO-A
13
What is EMSAM?
selegiline transdermal path for treatment of depression
- at low levels selegiline inhibits MAO-B but at antidepressent level inhibits A and B
- goal to bypass GI tract and liver to minimize chance of hypertensive crisis if tyramine is ingested
dietary restriction at > 6mg/24 hr
14
What kind of drug is phenelzine?
MAO inhibitor
15
What kind of drug is tranylcypromine?
MAO inhibitor
16
What kind of drug is selegiline?
MAO inhibitor --> selective for MAO-B at low doses; but acts on both at anti-depressant levels
17
What is therapeutic use for tricyclic antidepressants?
- major depression
- OCD [clomipramine]
- fibromyalgia
depression + treatment resistant depression
childhood enuresis [imipramine]
generalized anxiety disorder
insomnia
obsessive compulsive disorder
migraine
cataplexy syndrome [imipramine]
fibromyalgia
prurits/dermatologic
18
What is mech of action tricyclic antidepressants?
- block presynaptic reuptake of NE and 5HT
- secondary = NE only; tertiary = NE + 5HT
- causes NT accumulation in synaptic cleft
19
What are side effects of TCAs?
sedation, weight gain [H1 block]
a1 blockade --> orthostatic hypotension, dizziness
atropine [anti-ACh] side effects: urinary retention, dry mouth, tachycardia
20
What are side effects unique to despiramine?
- less sedating [H] but higher seizure incidence
- least alpha 1 blockade
21
Do tertiary or secondary amines have more anticholinergic effects?
tertiary > secondary
22
what are the Tri-C's of tricyclic antidepressants?
TriC = convulsion, coma, cardiotoxicity [arrhythmias]
23
Why should you use nortriptyline in elderly?
its a secondary amine = less anti-ACh effects
causes confusion and hallucination in elderly
24
How do you treat tricyclic antidepressant cardio toxicity?
NaHCO3
25
Which TCAs have least anticholinergic effects?
secondary amines [desipramine, nortriptyline]
26
Which TCAs have most antihistamigeric effect?
doxepin
27
Which TCAs have least alpha 1 blockade?
secondary amines [desipramine, nortriptyline]
28
What happens in TCA overdose?
lethal
29
Who should you avoid TCA in?
pts with narrow angle glaucoma, recent cardiac events, cardiac conduction delays, prolonged GTc
30
