117. Antidepressants Flashcards
Indications for Antidepressants
Psych: GAD, OCD, Panic Disorder, SoAD, PTSD, ADHD, Bulimia, Premenstrual Dysphoric Disorder, Insomnia, Smoking Cessation
Augment tx in Shizophrenia and BPD
for Medical Conditions: IBS, Enuresis, Neuropathic Pain, Fibromyalgia, Migraines
What is the monoamine theory of depression?
Monoamine: 5HT - synthesized in brain from tryptophan; DA/NE - made from tyrosine
NTs released into cleft, bind receptors in post-syn to alter fx and pre-syn receptors to suppress further release
NTs taken back into presyn terminal via reuptake - then degraded or stored
What are the tx principles of antidepressants?
Takes 3-8 weeks for maximum effect
Greatest improvement in severe depression
Tx: start low and increase dose every 1-2 weeks (takes up to 8-12 weeks to get adequate dose)
If no improvement, switch to another first line (same or diff class); if partial, add an adjunct
What are common Side Effects of Antidepressants?
GI upset, n/d, anxiety/agitation, insomnia, HA, Sweating, SEX DYSFX (persists)
Serotonin Syndrome: too much 5HT activity (multiple drugs) - causes AMS, autonomic hyperactivity, neuromuscular abnromalities (why MAOis are contraindicated with SSRIs)
Discontinuation syndrome - withdrawal sx when stopped (dizzy, HA, insomnia, nausea, malaise) - need for tapering off drug
Fluoxetine
- type
- feature
SSRI
longest half-life (long washout period)
Paroxetine
- type
- features
SSRI
- CYP2D6-inhibitor
- anticholinergic SE (sedation, constipation, weight gain)
- shortest half life (worst discontinuation syndrome)
Sertoline
- type
- features
SSRI
- high risk of GI SE
- preferred agent in PREGNANCY
Citalopram
- type
- feature
SSRI
- dose dependent QTc prolongation (avoid in cardiac comorbidity)
Escitalopram
- type
- feature
SSRI
- fewer SE than citalopram
Fluvoxamine
- type
- feature
SSRI
- only approved for OCD
Venlafaxine
- type
- feature
- similar drugs
SNRIs - low dose SSRI, high dose SNRI - good for neuropathic pain - risk of HTN at high dose Desvenlafaxine (active metabolite) Duloxetine
TCAs
- mechanism
- use
- SE
- inhibit NE/5HT reuptake
- used for chronic pain
SE: sedation, weight gain, anticholinergic (Dry mouth, constipation, urine retention, blurry vision), CV SE (orthostatic hypotension, dizziness, risk of serious arrythmias), seizure risk, lethal OD
What are the features of the following:
- Amitriptyline
- Imipramine
- Clomipramine
- Doxepin
- Nortriptyline
- Despiramine
- Amoxapine
Amitriptyline - tx migraines Imipramine - tx enuresis Clomipramine - tx refractory OCD Doxepin - tx insomnia (low dose) Nortriptyline - need TDM Amoxapine - antipsychotic metabolite
MAOi’s
- mechanism
- SE
- types
Mech: irreversibly inhibit MAO - prevent degradation of NE, 5HT, DA
SE: Orthostatic hypotension, drowsiness, Serotonin Syndrome risk
- Need special diet to avoid tyramine-rich food - risk HYPERTENSIVE CRISIS (severe HTN, stiff neck, sweating, n/v)
Types: Phenelzine, Tranylcypromide, Isocarboxazid, Selegiline
Bupropion
- mechanism
- SE
- use
- contraindication
- NE/DA reuptake inhibitor
- can WORSEN anxiety, activating antidepressent
SE: seizure, agitation, anxiety, insomnia, weight LOSS, dry mouth, HA, nausea
(no sex dysfx, no risk of provoking mania)
use: depression, ADHD, nicotine dependence, SSRI/SNRI induced sexual SE
CI: seizure disorder, eating disorder
