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RUSMpsychopharm7and8
Antidepressants
Question | Answer |
---|---|
Name 3 drugs known to INDUCE depression | reserpine: causes explosive release of amines of vessicles with no reuptake possible (initial excitement followed by depression). Iproniazide (MAO inhibitor used in TB |
What metabolite of NE is found in lower concentrations in the CSF of depressed pts? | MHPG (3methoxy-4-hydroxyphenol glycol) |
What metabolite of 5-HT is found in lower concentrations in the CSF of depressed pts? | 5-HIAA (5-hydroxy indole acetic acid) |
3methoxy-4-hydroxyphenol glycol (MHPG) is a metabolite of what NT | NE |
5-hydroxy indole acetic acid (5-HIAA) is a metabolite of what NT | 5-HT (remember as 5-HT makes HIAA--- both have H in the abbreviation) |
What is the function of varicosities? | diffusely projecting neuronal tracts that sets baseline tone in the CNS |
how long does it take for clinical effects to occur in TCADS | 2-4 wks |
what is the MOA of TCAD | blockade of cotransporters located presynaptically on NE and 5-HT nerve endings and cell bodies, especially in the limbic system (BLOCK 5-HT and NE reuptake) |
What are some toxic effects of TCAD | ****TRI-C's = Convulsions, Coma, and Cardiotoxicity***** |
Key features of TCADs (side effects, metabolism, use) | used for major depression, neuropathic pain relief and sometimes in nocturnal emesis. ATROPINE (**ANTICHOINERGIC**) LIKE side effects, CYP450 inhibitor. May cause impotence |
anti-depressants have what effect on the CNS (excite or depress? | Depress... this is why people on anti-depressants shouldn't drink EtOH |
What drugs are likely to have altered absorbance in pt taking TCADs? Why? | digoxin, Li, acetoaminiphen, levodopa. Anticholinergic effects of TCADs cause decreased GI activity. This can increase or decrease absorbance depending on where the drug is absorbed |
DOC for a depressed pt who is lethargic and tired | Imipramine. Action is most pronounced at preventing reuptake of NE. Has a stimulating effect on CNS (also blocks 5-HT reuptake, but to a lesser extent) |
DOC for a depressed pt who is overly anxious / has trouble sleeping | Amitryptaline. Action is most pronounced at it prevention of 5-HT reuptake. Depressing effect on CNS. (Also block NE reuptake, but to a less extent) |
DOC for OCD | Clomipramine |
What is the explanation for the delayed therapeutic response of antidepressants? | A period of time (2-4 weeks on avg) is required for the appropriate gene products to be synth'd and transported from cell body to nerve ending! |
Options for tx of panic disorder | Imipramine (TCAD that blocks NE and 5-HT reuptake... NE to a greater extent), alprazolam (benzo.... quicker acting), mirtazepine (atypical antidepressant), etc. |
Only approved tx for childhood depression is: | Fluoxetine |
side effects associated with 5-HT increase? | **REDUCTION OF EPILEPTIC THRESHOLD --> SEIZURES** ALSO DELAYED ORGASM nausea, diarrhea, anxiety, appetite suppression, |
Main differences between TCADs and SSRIs | SSRIs have: fewer side effects, less cardiotoxicity, less sedative, and less like to cause death from o/d |
Why should blood labs be ordered prior to rx'ing fluoxetine to a bulimic pt | Electrolyte levels must be checked because the chronic vomiting seen in bulimia can lead to hypokalemia and alkalemia, this can cause cardiac conduction abnormalities and convulsions. Important b/c fluoxetine lowers the threshold level for seizures |
what electrolyte imbalance is c/i with fluoxetine | hypokalemia (seen in bulemics) |
cyproheptadine is used for what? | To treat serotonin syndrome. Decrease serotonin levels (h-ht antagonist) |
What to drugs are used to treat serotonin syndrome | cyproheptadine and dantrolene |
What is the MOA of trazodone | Trazodone is an atypical antidepressant (does not inhibit 5-HT reuptake) The parent drug blogs 5-HT2, BUT its active metabolite (MCPP) is a 5-HT agonist! also blocks alpha-1 receptors (orthostatic htn) |
mnemonic for remembering heterocylic antidepressants | Bupropion, venlafaxine, mirtazapine, maprotiline, Trazodone. *You need BUtane in your VEINs to MURder for a MAP to alkaTRAZ" |
Major side effects of trazodone | *Exacerbation of ventricular arrhythmia*, orthostatic htn, and ***priapism*** |
Ventricular arrhthmia is most associated with what atypical antidepressent | trazodone |
What two drugs are c/i in pt with an eating disorder who is being treated for depression | bupropion (must not be given!), fluoxetine (order electrolyes to check for hypokalemia, but avoid if possible) |
Bupropion indications | pts who fail to responds to TCADs, nicotine withdrawal, and in depressed pts with cardiovascular problems (this drug has minimal CV effects) |
DOC for depressed pt with heart problems | bupropion |
nicotine withdrawal. Rx? | Bupropion |
Mirtzapine: MOA | Noradrenergic and Specific seratonergic antidepressant. Block 5-HT and NE autoreceptors and heteroreceptors located on 5-HT and NE nerve endings.... results in release of NE and 5-HT from the neurons on which they act |
What foods (specific foods)must be avoided in pts taking MAOI. What amine is in these foods and how does it affect pt / Why? | tyramine and octapamine. These amines displace NE --> increased NE present in high concentrations post-synaptically= CNS and CV crises. (Foods: cheeses, beer, pickled herring, figs, yogurt, etc. |
Compare MOA of trancyclopromine and phenelzine | Trancylopromine binds to both MAO A and MAO B with high affinity, phenelzine bind IRREVERSIBLY |
What MAO is metabolized by acetylation? | Phenelzine. Slow acetylators will show exaggerated fx |
What is important to remember when switching a pt from SSRI to MAOI or visa versa | must wait a period of 6 weeks because SSRI will inhibit the metabolism of the MAO-I, causing serotonin syndrome. Drug may remain in system for a longer period of time in slow acetylators |
What drug class is completely counterindicated with MAOI (results in hyperthermia, rigidity and coma). What other drugs are counterindicated? | ***meperidine (opioid) can cause death if given with MAO due to severe CNS depression*** |