Drugs Flashcards
What are the general classes of antidepressants?
- Old - MAOIs and TCAs
- New - SSRIs, NDRIs, SNRIs
Monoamine Hypothesis
- depression/anxiety results from inadequate monoamine neurotransmitter activity in brain so drugs work to inc monamine bioavailability
- Serotonin, dopamine, NE
MAOIs (examples, mechanism, side effects)
(phenelzine, tranyleypromine, selegine)
- Block monoamine oxidase; so block breakdown of all 3 in pre-synaptic neuron
- Hypertensive crisis if eat too much tyramine (cheese and wine) b/c displaces NE into synapse then MAOI inhibited; “cheese rxn”
TCAs (examples, mechanism, side effects)
(desipramine, nortriptyline, amitriptyline, imipramine, clomipramine)
-Dual agents; block both serotonin and NE reuptake channels on pre-synaptic surface
- Prolonged QT (torsades de pointes); must monitor + EKGs
- Anti-cholinergic (dry mouth, constipation and cog problems in elderly)
- Anti-histamine effects
SSRIs/SNRIs/NDRIs
(Fluoxetine, Paroxetine, Sertraline, Fluvoxamine, Citalopram, Escitalopram)
-Block just serotonin (or serotonin/NE or NE/dopamine) reuptake channels on pre-synaptic neuron surface
- Milder side effect profile and more safe if overdose
- May still have nausea, sexual problems, inc BP
For all SSRIs, wean off over weeks (unless fluoxetine)
What drugs are used to treat mania?
- mood stabilizers (lithium + anti-convulsants) OR anti-psychotics if psychotic symptoms
- Anti-convulsants include valproic acid, carbamazepine, lamotrigine
What drugs are used to treat anxiety disorders?
- Anti-depressants for prevention/maintenance BUT benzos for acute symptoms (mild sedative)
- Be careful of benzo dependence esp if quick acting drugs (like alprazolam - Xanax)
- Benzos = lorazepam, alprazolam, diazepam, clonazepam, chordiazepoxide
Dopamine Hypothesis of Schizophrenia
- Excess dopamine transmission in some brain circuits –> positive symptoms
- Relative deficit in dopamine transmission in motivation/attention/cog pathways –> negative symptoms
- SO…all anti-psychotics work by blocking D2 receptors
Old/Typical Anti-Psychotics + 4 Common Side Effects
(Haloperidol & Fluphenazine)
- Neuromuscular Risks (4)
- Extrapyramidal Symptoms (EPS)
- Tardive Dyskinesia
- Neuroleptic Malignant Syndrome
- Acute Dystonic Reaction
- SO… often co-administer w/ anti-cholinergic (cogentin)
New/Atypical Anti-Psychotics + Common Side Effects
(Risperidone, olanzapine, clozapine, quetiapine, ziprasidone, aripiprazole, paliperidone)
- Dual agents - combine D2 and 5HT2 receptor blocking
- Less potent so do not normally co-administer w/ anti-cholinergic
- Metabolic Risks -associated w/ metabolic syndrome (inc glucose, inc triglycerides, inc body weight, dec insulin sensitivity, inc hypertension)
- MONITOR
4 Dopamine Pathways
Mesolimbic - elevated in schizo so balanced w/ drugs; reduces positive symptoms
Mesocortical - reduced in schizophrenia but further reduced by drugs; more negative symptoms
Nigrostriatal - normal in schizophrenia; dampened with drugs; Parkinsonianism
Tuberoinfundibular - normal in schizophrenia; dampened w/ drugs –> hyperprolactinemia
Extra-Pyramidal Symptoms
Slow movement, tremor, mild muscle rigidity
Reversible so stop med; Give w/ anti-cholinergic from start
Tardive Dyskinesia
Irregular, writhing movement (mouth, tongue, extremities)
**B/c make more D2 receptors to comp
Inc risk over time taking med
Switch to atypical w/ less potent D2 block; Anti-cholinergics do NOT help
Neuroleptic Malignant Syndrome
Acute, extreme muscle rigidity (lead pipe); Can also be confused and febrile
Muscles breakdown from rigidity –> CK in blood; CK can clog kidneys –> life threatening renal failure
Stop antipsychotic; Flush w/ IV fluids; Benzos to relax muscles; Administer dopamine receptor agonist (bromocriptine)
Acute Dystonic Reaction
Sudden onset intense contraction of single muscle group; PAINFUL
Single IM injection of anti-cholinergic –> instant reversal; Then give med w/ anti-cholinergic in future
