Antipsychotics - FGA's Flashcards
Potency of FGA’s
There’s low and high potency
Binding affinity correlated with anti-psychotic effects
What are the 3 FGA classes?
PhenothiAZINES
Thioxanthines
Butyrophenones
What was the first psychotropic medication
Chlorpromazine
What are the Phenothiazines and what are their potencies
- Low potency = Chlorpromazine and Thioridazine
- Moderate potency = Perphenazine
- High potency = Trifluoperazine and Fluphenazine
What is the thioxanthine and what is its potency?
Thiothixene -moderate potency
What is the Butyrophenone and what is its potency?
Haloperidol - high potency
What does it mean to be a low potency FGA?
Low D2 binding affinity, need a larger dose
What does it mean to be a high potency FGA?
High D2 binding affinity, need a smaller dose
Compare the potencies of Haloperidol and Chlorpromazine
Chlorpromazine is a lower potency drug compared to Haloperidol
What’s the MOA of FGA’s?
antipsychotic effect is by blocking DA receptors, but blocking of non-DA receptors (histamine, adrenergic, and muscarinic) gives side effects
What percent of mesolimbic tract needs to be blocked to get an effect? What is this effect?
Antipsychotic effect
Via blocking >60-65% of D2 receptors
What percent of nigrostriatal and tuberoinfundibular tracts need to be blocked to get an effect? What is this effect?
Side effects - EPS and Inc prolactin
Blocking >80% of the D2 receptors
What’s the therapeutic window?
Blocking 60/65% - 80% of D2 receptors
Blocking >80% of the nigrostriatal tract D2 receptors gives?
EPS/Tardive dyskinesia
Blocking >80% of the tuberoinfundibular tract D2 receptors gives?
Hyperprolactinemia
What side effects are associated with DA receptors?
EPS, Tardive dyskinesia, Hyperprolactinemia
What side effects are associated with muscarinic receptors?
Blurred vision, dry mouth, urinary retention, constipation, confusion
*Can’t see, can’t pee, can’t spit, can’t S**T
What side effects are associated with histamine receptors?
Sedation and weight gain
What side effects are associated with alpha-1 adrenergic receptors?
Orthostatic hypotension and a risk of falling
What receptor side effects are seen with haloperidol vs chlorpromazine?
See all receptor side effects with chlorpromazine and only D2 side effects with haloperidol (so they may be more likely to give EPS signs)
What are EPS?
Drug induced Parkinsonism (resting tremor, bradykinesia, stiffness)
Dystonia
Akathesia
What does drug induced Parkinsonism for EPS entail?
Resting tremor: improves with posture Essential tremor: goes way at rest Akinesia and Brady-/Hypo-kinesia: slowness, loss of autonomic movements (ex: blinking), difficulty initiating movements Rigidity (cogwheel) Impaired posture/balance Speech/voice changes
What does Dystonia for EPS entail?
Sustained abnormal posture /involuntary muscle spasms (often worse w/ activity)
Often happens very early in treatment - within ~2 weeks
What group is at an increased risk for EPS dystonia?
Young males
Complaints of an allergic reaction to psychotic meds often refers to?
Dystonic reaction
What does Akathesia for EPS entail?
Inner sense of restlessness & need to move
Patientss find it especially distressful
What group is at an increased risk for EPS akathesia?
Women at an inc risk (2x > men)
Akathesia can be mistaken for?
Can be mistaken for becoming agitated.
But if you give them MORE antipsychotics to treat the ‘agitation’ it will make it worse
What does Tardive dyskinesia for EPS entail?
Abnormal involuntary movement from taking DA blockers
Typically does not remit even after stopping DA blocker
Sometimes resembles chorea, dystonia, myoclonus, tics or tremor
What types of movements/regions is more affected by tardive dyskinesia?
Classically, especially lower facial and tongue movements
Ex: Grimacing!
Can also be upper/lower extremities or trunk
Hyperprolactinemia can result in?
Galactorrhea/lactation and gynecomastia
Dec GnRH (dec LH and FSH)
Osteopenia (inc risk of fractures)
