CNS Drugs (Psychotherapeutic, anti-Parkinson's) Flashcards
Parkinson’s symptoms are caused by an imbalance of ______ and _______ because ______-producing neurons are lost.
(fill in the three blanks with either dopamine or acetylcholine)
Parkinson’s symptoms are caused by an imbalance of dopamine and acetylcholine because dopamine-producing neurons are lost.
Direct and Indirect DA System drugs
name one direct and two indirect
also name one anticholinergic for fun
direct: DA receptor agonists
indirect: levodopa-carbidopa, selegiline (MAOI)
anticholinergic: benztropine
Indirect: Levodopa-carbidopa what is levodopa? how long until levodopa therapy fails? AEs Care
a precursor to dopamine (it can cross the BBB, but dopamine cannot). it’s very similar to a cyclic amino acid.
fails between 5 and 10 years after starting
AEs: nausea, vomiting, dyskinesia (large flinging movements of arms/legs, chewing motions), psychosis
Care: hypotension, dizziness, must avoid high protein foods/diet (because amino acids competitively reduce GI absorption and transport across BBB), dark urine and sweat (harmless).
- taking levodopa with non-selective MAOIs (antidepressants) can cause hypertensive crisis
Combination therapy
why give levodopa with carbidopa?
what do COMT inhibitors do? name one
carbidopa stops conversion of levodopa from happening in the PNS, because we want it to be converted in the brain (CNS)
COMT inhibitors stop the breakdown of levodopa to an inactive substance.
entacapone is an example
Indirect: Selegiline
it’s a MAOI - what does this mean?
Mechanism
It is a selective monoamine oxidase-B inhibitor. MAO-B breaks down dopamine in the presynaptic terminal, and selegiline stops this
Mechanism: irreversibly binds and inhibits MAO-B (but you don’t get the “cheese” effect because it’s selective for just B and doesn’t affect MAO-A)
it’s used as an adjunctive agent alongside levodopa
Direct: DA Receptor Agonists
1st line treatment for PD, but we didn’t discuss them because they have lots of adverse side effects like hallucinations and impulse-control disorders
Anticholinergic agents - background
are cholinergic pathways excitatory or inhibitory?
what do we see as a result of unrestrained cholinergic activity?
cholinergic pathways are excitatory
we see muscle tremors, cogwheel rigidity, pin-rolling and head-bobbing
Anticholinergic agents name one Indications AEs (4) Care
benztropine
Indications: muscle tremors associated with PD (but do NOT relieve bradykinesia), and drug-induced extrapyramidal symptoms
AEs: typical anticholinergic effects (dry mouth, constipation, urinary retention blurred vision)
Care: assess for signs of PD - masklike expression, dysphagia. assess for signs of it working like less tremor and more relaxed muscles
Psychotherapeutics
Treatment of emotional and mental disorders (anxiety, mood disorders, and psychoses)
Antidepressants
Newer-generation
name two classes
Older-generation
name two classes
newer: SSRIs and SNRIs
older: TCAs and MAOIs
make sure you know what the abbreviations mean
SSRIs name one time to take effect mechanism benefits compared to older gen Indications AEs Serotonin syndrome (when, signs?)
sertraline (Zoloft)
may take 2-6 weeks to take effect
mechanism: blocks reuptake of 5-HT (serotonin) into the presynaptic terminal
benefits: no effect on CV system and fewer drug/food interactions
Indications: major depressive disorder, bipolar affective disorder, eating disorders, OCD
AEs: sexual dysfunction, weight gain
SS: within 2-72 hours, confusion, tachycardia, hypertension, tremor
SNRIs
name one
therapeutic/adverse effects
venlafaxine
effects same as SSRIs
TCAs name one Indications mechanism AEs
Amitriptyline (largely replaced by SSRIs and SNRIs)
Indications: depression, childhood enuresis (use imipramine)
mech: blocks both NE and 5-HT reuptake (yay) but also alpha-adrenoreceptors (oh no)
AEs: sedation, anticholinergic effects, orthostatic hypotension (from a1 blockage)
SERIOUS: cardiac dysrhythmia, seizures
overdose can be lethal, with no antidote except activated charcoal
MAOIs
mechanism
AEs
Care
mechanism: inhibit MAO enzyme in CNS
AEs: orthostatic hypotension, hypertensive crisis (the cheese effect) due to ingestion of tyramine - you get severe headache, hypertension, tachycardia
- because tyramine causes release of NE leading to increase in BP
Care: may take 2 to 4 weeks to see effects
Foods that contain tyramine
aged/mature cheeses, smoked/pickled meats, yyeast extracts, red wines
