21. Psychiatric Disease

Question 1

How do selective serotonin reuptake inhibitors (SSRIs) work? What are some examples?

Answer 1

SSRIs prevent reuptake of serotonin in the synaptic cleft that increases the amount of serotonin, which enhances neurotransmission

• Citalopram, escitalopram, fluoxetine, paroxetine, sertraline

Question 2

How do selective serotonin-norepinephrine reuptake inhibitors (SNRIs) work? What are some examples?

Answer 2

SNRIs prevent reuptake of serotonin and norepinephrine in the synaptic cleft that increases the amount of serotonin and norepinephrine, which enhances neurotransmission

• Duloxetine, venlafaxine, desvenlafaxine, milnacipran, and levomilnacipran

Question 3

How do tricyclic antidepressants (TCAs) work?

Answer 3

TCAs prevent reuptake of serotonin and norepinephrine in the synaptic cleft that increases the amount of serotonin and norepinephrine, which enhances neurotransmission

• Clomipramine, imipramine, amitriptyline, nortriptyline, and protriptyline

Question 4

How do monoamine oxidase inhibitors (MAOIs) work?

Answer 4

MAOIs inhibit the activity of monoamine oxidase, thus preventing the breakdown of monoamine neurotransmitters such as serotonin, epinephrine, and norepinephrine.

• Isocarboxazid, nialamide, phenelzine, tranylcypromine, bifemelane, moclobemide, pirlindole, rasagiline, selegiline

Question 5

What is major depressive disorder

Answer 5

Depressed mood that lasts at least 2 weeks with a constellation of associated symptoms (SIGECAPS)
- Sleep
- Interest
- Guilt
- Energy
- Cognition/concentration
- Appetite
- Psychomotor
- Suicide

Question 6

What are four classes of antidepressants?

Answer 6

SSRIs, SNRIs, TCAs, MAOIs

Question 7

What is bipolar disorder

Answer 7

AKA manic depression
Mental disorder with periods of depression and mania (elevated mood).

Question 8

Treatment for bipolar disorder

Answer 8

Antidepressant and mood stabilizer

Question 9

Mood stabilizers

Answer 9

Lithium, anticonvulsants, and antipsychotics

Question 10

How does lithium toxicity manifest?

Answer 10

Cardiac toxicity (AV blocks, sinus bradycardia, ventricular irritability), seizures, hypotension.

Narrow therapeutic index. Avoid steroids and ibuprofen in these patients (may increase lithium bioavailability).

Question 11

What is serotonin syndrome?

Answer 11

An adverse drug reaction producing excess serotonergic effects of the central nervous system.
- Occurs shortly after an increase in the dose of a serotonin agonist (MOI or SSRI inhibitor) or after the addition of a second serotonergic agent such as tramadol or dextromethorphan.
- Changes in mental status, neuromuscular activity, and autonomic function.

Question 12

Symptoms of serotonin syndrome

Answer 12

Hypertension, diarrhea, tachycardia, hyperthermia, diaphoresis, ataxia, myoclonus, mydriasis, hallucinations, confusion

Question 13

How is serotonin syndrome treated?

Answer 13

Lorazepam 1-2mg IV push for agitation

Methysergide 2-6 mg to counteract serotonin

Labetalol or propranolol for HTN and tachycardia

Cyproheptadine 4mg PO to counteract serotonin

Question 14

What can occur as a result of serotonin syndrome?

Answer 14

Rhabdomyolysis, ventricular arrhythmia, respiratory arrest, and coma

Question 15

What drugs can trigger serotonin syndrome?

Answer 15

Fentanyl
Tramadol
Ondansetron

Question 16

Patients on TCAs have INCREASED/DECREASED effects to vasoconstrictors

Answer 16

Vasoconstrictors have EXAGGERATED effects in patients on TCAs

Question 17

What drug should be avoided in patients on MAOIs?

Answer 17

Ephedrine

Question 18

What is schizophrenia?

Answer 18

A psychiatric disorder characterized by chronic and recurrent psychosis in the form of positive and negative symptoms
- Positive symptoms: hallucinations, delusions, disorganized thoughts and speech, bizarre behavior
- Negative symptoms: apathy, flat affect, anhedonia, aloofness, cognitive impairment

Question 19

Treatment of schizophrenia

Answer 19

Antipsychotics
- First generation antipsychotics: dopamine receptor blockade and effects on other receptors such as serotonin type 2 (5-HT2), alpha-1, histaminic, and muscarinic receptors. [Haloperidol, fluphenazine, chlorpromazine, perphenazine]
- Second generation antipsychotics: D2 blockade with reduced extrapyramidal side effect profile. [Risperidone, clozapine, olanzapine, lurasidone, quetiapine, ziprasidone].

Question 20

What are extrapyramidal side effects?

Answer 20

Effects on other receptors such as serotonin type 2, alpha-1, histaminic, and muscarinic receptors.

• Rigidity
• Bradykinesia
• Dystonias
• Tremor
• Akathisia
• Tardive dyskinesia
• Prolonged QT interval

Question 21

What is neuroleptic malignant syndrome?

Answer 21

Potentially fatal complication of dopamine antagonist due to depletion of dopamine in the CNS. Manifests over 24-72 hours.
- Rigidity, AMS, pyrexia, elevated creatine kinase, autonomic instability, DIC, respiratory failure from chest wall rigidity

Slower in onset than serotonin syndrome

Question 22

Treatment of NMS

Answer 22

Withdrawal of dopamine antagonist offending agent.

Supportive therapy, replenish electrolytes, antipyretics, cooling blankets, control BP, mechanical ventilation, BZDs, bromocriptine