Antipsychotics - FGA's

Question 1

Potency of FGA’s

Answer 1

There’s low and high potency

Binding affinity correlated with anti-psychotic effects

Question 2

What are the 3 FGA classes?

Answer 2

PhenothiAZINES
Thioxanthines
Butyrophenones

Question 3

What was the first psychotropic medication

Answer 3

Chlorpromazine

Question 4

What are the Phenothiazines and what are their potencies

Answer 4

• Low potency = Chlorpromazine and Thioridazine
• Moderate potency = Perphenazine
• High potency = Trifluoperazine and Fluphenazine

Question 5

What is the thioxanthine and what is its potency?

Answer 5

Thiothixene -moderate potency

Question 6

What is the Butyrophenone and what is its potency?

Answer 6

Haloperidol - high potency

Question 7

What does it mean to be a low potency FGA?

Answer 7

Low D2 binding affinity, need a larger dose

Question 8

What does it mean to be a high potency FGA?

Answer 8

High D2 binding affinity, need a smaller dose

Question 9

Compare the potencies of Haloperidol and Chlorpromazine

Answer 9

Chlorpromazine is a lower potency drug compared to Haloperidol

Question 10

What’s the MOA of FGA’s?

Answer 10

antipsychotic effect is by blocking DA receptors, but blocking of non-DA receptors (histamine, adrenergic, and muscarinic) gives side effects

Question 11

What percent of mesolimbic tract needs to be blocked to get an effect? What is this effect?

Answer 11

Antipsychotic effect

Via blocking >60-65% of D2 receptors

Question 12

What percent of nigrostriatal and tuberoinfundibular tracts need to be blocked to get an effect? What is this effect?

Answer 12

Side effects - EPS and Inc prolactin

Blocking >80% of the D2 receptors

Question 13

What’s the therapeutic window?

Answer 13

Blocking 60/65% - 80% of D2 receptors

Question 14

Blocking >80% of the nigrostriatal tract D2 receptors gives?

Answer 14

EPS/Tardive dyskinesia

Question 15

Blocking >80% of the tuberoinfundibular tract D2 receptors gives?

Answer 15

Hyperprolactinemia

Question 16

What side effects are associated with DA receptors?

Answer 16

EPS, Tardive dyskinesia, Hyperprolactinemia

Question 17

What side effects are associated with muscarinic receptors?

Answer 17

Blurred vision, dry mouth, urinary retention, constipation, confusion

*Can’t see, can’t pee, can’t spit, can’t S**T

Question 18

What side effects are associated with histamine receptors?

Answer 18

Sedation and weight gain

Question 19

What side effects are associated with alpha-1 adrenergic receptors?

Answer 19

Orthostatic hypotension and a risk of falling

Question 20

What receptor side effects are seen with haloperidol vs chlorpromazine?

Answer 20

See all receptor side effects with chlorpromazine and only D2 side effects with haloperidol (so they may be more likely to give EPS signs)

Question 21

What are EPS?

Answer 21

Drug induced Parkinsonism (resting tremor, bradykinesia, stiffness)
Dystonia
Akathesia

Question 22

What does drug induced Parkinsonism for EPS entail?

Answer 22

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

Question 23

What does Dystonia for EPS entail?

Answer 23

Sustained abnormal posture /involuntary muscle spasms (often worse w/ activity)

Often happens very early in treatment - within ~2 weeks

Question 24

What group is at an increased risk for EPS dystonia?

Answer 24

Young males

Question 25

Complaints of an allergic reaction to psychotic meds often refers to?

Answer 25

Dystonic reaction

Question 26

What does Akathesia for EPS entail?

Answer 26

Inner sense of restlessness & need to move

Patientss find it especially distressful

Question 27

What group is at an increased risk for EPS akathesia?

Answer 27

Women at an inc risk (2x > men)

Question 28

Akathesia can be mistaken for?

Answer 28

Can be mistaken for becoming agitated.

But if you give them MORE antipsychotics to treat the ‘agitation’ it will make it worse

Question 29

What does Tardive dyskinesia for EPS entail?

Answer 29

Abnormal involuntary movement from taking DA blockers
Typically does not remit even after stopping DA blocker
Sometimes resembles chorea, dystonia, myoclonus, tics or tremor

Question 30

What types of movements/regions is more affected by tardive dyskinesia?

Answer 30

Classically, especially lower facial and tongue movements
Ex: Grimacing!
Can also be upper/lower extremities or trunk

Question 31

Hyperprolactinemia can result in?

Answer 31

Galactorrhea/lactation and gynecomastia
Dec GnRH (dec LH and FSH)
Osteopenia (inc risk of fractures)