Pharmacology/Psychiatry - Antidepressants Flashcards
Re-uptake inhibitors immediate action?
Increase levels of neurotransmitters = more opportunity to bind to receptor
Re-uptake inhibitors delayed action?
Down-regulation of neurotransmitter receptors
What might explain the reason for time needed to see antidepressant effect?
Re-uptake inhibitor delayed action - down-reg of NT receptors
Sustained antidepressant therapy is also associated with increase in production of what?
BDNF - brain derived neurotrophic factor
Antidepressant suicide risk is increased in which populations (in general)?
Children, adolescents, and adults up to 24 yo.
What are SNRI’s? Examples?
Serotonin and Norepinephrine Re-uptake Inhibitors
- Ex: Tricyclic Antidepressants (TCA) - amitriptyline
- Ex: Venlafaxine
What are SSRI’s? Example?
Selective Serotonin Re-uptake Inhibitors
- Ex: Fluoxetine
What are MAOI’s? Example?
Monoamine Oxidase Inhibitors
Ex: Trazodone
One of the first types of antidepressants discovered?
TCAs
Mechanism of TCAs?
They are classified as SNRI’s = block the re-uptake of serotonin and norepinephrine so they can hang around in synaptic cleft and exert their effects
Adverse effects of TCAs?
Block receptors for M-receptors, alpha-1 and Histamine-1 receptors
Adverse effect of blocking M-receptors? (4)
- Salivary glands = dry mouth
- Intestines = constipation
- Bladder = urinary retention
- Pupil = dilation
Adverse effect of blocking alpha-1 receptors on blood vessels? (3)
- Orthostatic hypotension
- Sedation
- Sexual dysfunction
Adverse effects of blocking histamine-1 receptors? (2)
- Weight gain
- Drowsiness
Sexual dysfunction is caused by serotonin acting on what receptor?
5-HT2a receptors
What can TCA overdose lead to?
Life-threatening cardiac arrhythmias
How does Venlafaxine differ from TCA’s?
- it also weakly inhibits dopamine re-uptake
- has less significant alpha-1, H-1 and M-1 block
Most commonly prescribed antidepressant class?
SSRI’s
Adverse effects of SSRI’s?
- Often related to M, alpha-1 and H-1 block but typically more mild than TCAs (except sexual dysfunction)
SSRI’s have the potential to cause what?
Serotonin syndrome
Triad of sx of serotonin syndrome?
- Altered mental status
- Autonomic hyperactivity
- Neuromuscular abnormalities
Altered mental status ex?
Agitation
Autonomic hyperactivity ex?
Patient is often hot and sweating with a fast HR and high BP
Neuromuscular abnormalities ex?
Hyper-reflexia and clonus are particularly common in lower extremities
Medication to interfere with serotonin action in serotonin syndrome?
Cyproheptadine
Symptomatic treatment of serotonin syndrome?
Treat with benzodiazepines
Therapeutic mechanism of MAOI’s?
Block monoamine oxidase = enzyme that metabolizes norepinephrine -> higher levels of norepinephrine
When can MAOI’s induce a hypertensive crisis?
when combines with foods containing tyramine
Medication that inhibits serotonin re-uptake but is NOT considered an SSRI?
Trazodone
Trazodone acts directly as an antagonist at what serotonin receptors?
5-HT2A receptors
Adverse effects of Trazodone?
- H1-block and potent alpha-1 block = strong sedative
- Weight gain (minimal)
Antidepressant Bupropion? what is the non-anti-depressant version used for?
Antidepressant = Wellbutrin
Smoking cessation therapy = Zyban
Wellbutrin mechanism of action?
Weak inhibition of norepinephrine and dopamine reuptake
Adverse effects of Wellbutrin?
Dose related seizure risk
