Antidepressants Flashcards
to make serotonin, what is needed?
tryptophan
what are the side effects of SSRIs?
tremors (intentional tremor), nausea, headache, agitation, nervousness, loss of labito and sexual function
why does it take several weeks for SSRIs to be effective?
-they increase the serotonin in the synaptic cleft, but with that increase, the serotonin (5-HT) acts on the auto receptors which in turn down regulate the production of serotonin. Eventually, the SSRIs produce desensitization of the auto receptors, and it takes a while for this to happen
serontonergic syndrome
bc of the increase of serotonin from SSRIs and SNRIs patients can have
- tachycardia, htn,
- psychiatric manifestations (manic, elevated mood, confusion, hyperactivity),
- GI (cramping, bloating, diarrhea), and
- neurological (tremolo usness, incoordination)
- Big ones: diaphoresis (sweating), hyperthermia, and death by cardiovascular collapse
drug interactions of SSRIs and SNRIs
with MAO inhibitors the admin of antidepressants within 2 weeks of the discontinuation of MAO inhibitors can rest in SEVERE HYPERTENSIVE CRISIS or in the case of SSRI’s a serotonin syndrome consisting of hyperthermia, muscle rigidity and confusion
which antidepressant produces severe discontinuation syndrome if not tapered off?
Paxil
how would you treat an overdose of antidepressants? (esp tricyclics)
Physostigmine
what drug(s) is/are used to treat serontonergic syndrome?
cyproheptadine (oral) and chlorpromazine (IV)
Fenfluramine
a 5-HT (serotonin) releasing drug
fluoxetine
blocks reuptake of 5-HT (serotonin) and thus increases 5-HT
what does MAO do?
degrades 5-HT (serotonin) to HIAA
which drugs (class) block the reuptake of monoamines (particularly NE and/or serotonin) into presynaptic neurons
tricyclic antidepressants and SSRI’s
what are the original tricyclic antidepressants?
- imipramine and its N-demethylated counterpart DESIPRAMINE. also
- amitriptyline and it’s N-demethylated counterpart NORTIPTYLINE and
- Doxepine
how do tricyclic antidepressants work?
-block the reuptake of NE and Serotonin
which tricyclics have a greater specificity for serotonin and what are they more useful for?
the tertiary amines (imipramine and amitriptyline) and are somewhat more sedating
which tricyclics have greater specificity for NE?
the demethylated secondary amines (desipramine and nortriptyline), these are less sedating
this drug is relatively specific for dopamine uptake inhibition, lacks sedative effects, has a low incidence of anticholinergic effects, but may be associated with an increased risk of seizures
Buproprion (Wellbutrin)
-it is a “second generation” antidepressant
the drug is approved specifically for txt of obsessive -compulsive disorders (OCD). In most respects its pharmacology resembles nonselective tricyclics
Clomipramine (Anafranil)
which drug is the most commonly used antidepressant?
Fluoxetine (Prozac)
compare the side effects of SSRI’s and traditional tricyclics
- They are less likely to cause sedation, orthostatic hypotension, ! !tachycardia, cardiotoxicity, seizures, weight gain, blurred vision or dry !mouth. !
- The most frequent side effects of SSRI’s are nausea, headache, tremor, !insomnia or somnolence, agitation and nervousness. !
- They are at least as likely as tricyclics to cause impairment of sexual !function, presenting a significant problem for many patients. !
- There is also some question whether they are as effective as older tricyclics !for severe depression and would not be as useful for depressed patients who !would benefit from some sedation. Fluoxetine and fluvoxamine have been !specifically approved for treatment of OCD
what drugs could be used to treat OCD?
- clomipramine
- fluoxetine (prozac)
- fluvoxamine
which drug has dual action and thus blocks the reuptake of both 5-HT and NE?
venlafaxine
-mirtazepine also has dual action, it has serotonergic and noradrenergic effects
which antidepressant has a long duration of action and active metabolites that can lead to accumulation and slow return to drug-free status. (thus a shorter duration drug may be indicated is some cases like elderly pts)
-fluoxetine (prozac)
***chronic txt of animals with SSRI antidepressants causes:
- desensitization and down-regulation of serotoninergic auto receptors that regulate:
- the firing rate of raphe neurons (somatodendritic auto receptors)
- the synthesis of serotonin (presynaptic auto receptors)
- the release of serotonin (presynaptic auto receptors)
- A marked increase in synaptic levels of 5-HT in the continued presence of uptake blockade as a result of removal of the negative feedback loops by desensitization and down-regulation
