155. Antipsychotics

Question 1

List 8 adverse effects of antipsychotics

Answer 1

Blockade of dopamine
Dopamine-mediated meningeal artery vasodilation
Weight gain
Dyslipidemia
Glucose intolerance
New-onset diabetes
Metabolic syndrome

Question 2

5 off target receptors and the SE they produce

Answer 2

Alpha-1 adrenergic receptor antagonism
- Orthostatic hypotension
Muscarinic acetylcholine receptor antagonism
- Anticholinergic toxicity
Histamine H1 receptor antagonism
- Sedation
Fast voltage-gated sodium channel blockade
- Wide complex dysrhythmias
Delayed potassium rectifier channel blockade
- QT prolongation and, potentially, Torsade’s de Pointes

Question 3

List 4 physiological effects of antipsychotics in acute overdose

Answer 3

1. CNS depression is common
2. Mild sedation to coma
3. Anticholinergic delirium and agitation
4. Airway reflexes can be impaired and respiratory depression can occur after overdose.
5. Pupils may be of variable size
6. Anticholinergic effects promote mydriasis, whereas miosis, resulting from alpha-antagonism, may mimic opioid toxicity.
7. Mild orthostatic hypotension is also a common finding from alpha-adrenergic blockade
8. Seizures
9. EPS symptoms

Question 4

List 4 low potency FGAs

Answer 4

Chlorpromazine, fluphenazine, perphenazine, promethazine, thiordazine

Question 5

List 4 high potency FGAs

Answer 5

Droperidol, haloperidol, loxapine, pimozide, thiothixene, trifluoperazine

Question 6

List 5 atypicals

Answer 6

Aripiprazole, asenapine, clozapine, iloperidone, lutasidone, olanzapine, paliperidone, quetiapine, risperidone, ziprasidone

Question 7

Common SE of SGAs

Answer 7

Impaired glucose tolerance
Weight gain
Dyslipidemias
Metabolic syndrome
Movement disorders also occur with SGAs but with lower frequency

Question 8

SE of FGAs

Answer 8

• In general, low-potency FGAs are the most sedating
• First generation or typical antipsychotics produce more extrapyramidal symptoms (e.g., tardive dyskinesia, Parkinsonian syndrome, akathisia)

Question 9

Describe 4 common extrapyramidal reactions in antipsychotic use other than NMS

Answer 9

Dystonic Reaction
- Oculogyric crisis (eyes rolling back in head)
- Opisthotonos (severe hyperextension spasm of head, neck, spine)
- Torticollis
Akathisias
- Feeling of motor restlessness
Parkinsonism Trap
- Tremor
- Rigidity
- Akinesia / bradykinesia
- Postural instability
Tardive Dyskinesia
- Choreiform movements
- Lip smacking
- Chronic/difficult to treat

Question 10

MGMT of EPS

Answer 10

3 Bs
Benadryl 50mg PO/IV
Benztropine 2mg PO/IV
Benzodiazepines

Question 11

Describe the diagnostic criteria for NMS

Answer 11

Exposure to a dopamine antagonist or withdrawal of a dopamine agonist within 72 hours
Hyperthermia (>38 degrees Celsius) on at least two occasions, measured orally
Rigidity
Mental status alteration
Creatinine kinase elevation (at least four times the upper level of normal)
Sympathetic nervous system lability, defined as at least two of the following:
- Blood pressure fluctuation (>/20% DBP change or >/25% SBP change in 24 hours)
- Diaphoresis
- Urinary incontinence
- Hypermetabolic state (heart rate >/25% and respiratory rate >/50% above baseline)
- Negative evaluation for other toxic, metabolic, infectious, or neurologic causes

Question 12

List 3 other most likely DDx of NMS

Answer 12

Serotonin Syndrome
Malignant or Lethal Catatonia
Sympathomimetic Toxicity
Malignant hyperthermia
Heatstroke

Question 13

Describe the management of NMS

Answer 13

Stop offending medication
Hydration
Active cooling
IV benzodiazepines
Non-depolarizing neuromuscular blockade
Limited evidence: Dantrolene
Dopamine agonists (e.g., bromocriptine)
Consider ECT for refractory cases

Question 14

RFs for NMS

Answer 14

o	Rapid dose increase
o	High potency
o	Paraenteral forms
o	Dehydration
o	Brain injury
o	Previous NMS

Question 15

MGMT of cardio toxicity

Answer 15

• monitors
  -if QRS wide
  o Na bicarb
  -Hypotension
  o Fluids
  -Correct lyte abnormalities
  -If QT > 500 or any torsades, should give MgSO4 – 2-4g