Psych ppt (Part 1) Flashcards
How long does it take for tricyclic antidepressants (TCA) to work?
only after 2 - 3 weeks of chronic dosing will a therapeutic benefit emerge
What is thought to be the mechanism of action of TCAs?
- inhibition of norepinephrine neuronal reuptake
- time dependent changes in beta adrenergic function parallel the delayed onset of clinical efficacy
- mild effect on 5-HT central serotonin receptor sensitivity
What is the half life range of TCAs?
8 - 89 hours or redonkulously long either answer will be accepted
TCAs undergo metabolism where?
the liver (through oxidative metabolism)
TCAs cause an antimuscarinic effect. What are antimuscarinic effects?
tachycardia blurred vision constipation dry mouth
Other adverse effects seen with TCAs.
sedation
toxic delirium
seizures
weight gain
involuntary movements
neuroleptic malignant syndrome
All TCAs are weak _____ adrenergic antagonists.
alpha
(most common CV effects are orthostatic hypotension and tachycardia)
How is sedation thought to be mediated with TCAs?
through antagonist properties at the alpha 1-adrenoceptor and H1-histaminergic receptor sites in the brain
Overdose of TCA are frequently fatal with unresolvable __________.
arrythmias
Selective serotonin reuptake inhibitors (SSRI) produce therapeutic action through an ability to do what?
modulate serotonin neurotransmission in the brain
Biggest clinical difference with TCAs and SSRIs, in my opinion.
- the side effect profile is much different between the two and better tolerated with SSRI
(ie. the anticholinergic and CV side effects were not present in the SSRI group)
Common side effects of SSRIs?
GI: nausea and diarrhea, weight loss
CNS: insomnia and anxiety
Sexual: aorgasmia and delayed ejaculation
Caution must be used when SSRIs are used in combination with other antidepressants, benzodiazepines, neuroleptics, and carbamepazine. Why?
because the blood levels of SSRIs will increase
What is the half life of SSRIs?
2 - 3 days
(not bad, compared to TCAs of 8 - 89 days)
Monoamine oxidase inhibitors (MAOI) are reserved for what conditions?
- atypical depression
- depression unresponsive to TCAs or SSRIs
- depression resistant to electo-convulsive therapy (ECT)