Chapter 177: Cyclic Antidepressants

Question 1

It is a muscle relaxant that is almost structurally identical to amitriptyline but lacks antidepressant activity, and serious toxicity from overdose is rare?

Answer 1

Cyclobenzaprine

Question 2

It is a tetracyclic (also termed a heterocyclic), with a four-ring central structure plus a side chain?

Answer 2

Maprotiline

Question 3

True or False
Tertiary amines are generally more potent in blocking reptake of serotonin compared to blocking reuptake of norepinephrine, also cause more anticholinergic side effects (e.g., constipation or blurred vision) and are also highly sedating because of their central effects on histamine receptors

Answer 3

True
Tertiary amines are generally more potent in blocking reptake of serotonin compared to blocking reuptake of norepinephrine

Question 4

Sample of secondary amines cyclic antidepressants

Answer 4

• Desipramine
• Nortriptyline
• Protriptyline

Question 5

Has a three-ring central structure and a side chain that differs from the other tricyclics. It is a potent norepinephrine reuptake inhibitor and also blocks postsynaptic dopamine receptors

Answer 5

Amoxapine

Question 6

The only antidepressant that has antipsychotic effects and can produce seizure with minimal warning and normal QRS complex

Answer 6

Amoxapine

Question 7

The most important factor contributing to patient mortality in Cyclic antidepressant

Answer 7

Cardiotoxicity

Question 8

Cardiac conduction abnormalities occur during cyclic antidepressant poisoning because inhibition of?

Answer 8

Fast sodium channels in the His-Purkinje system and myocardium decreases conduction velocity,

Question 9

The effect seen in ECG in patient taking cyclic antidepressants

Answer 9

QT interval prolongation which is more pronounced at slow heart rate

Question 10

True or False

Tissue cyclic antide-pressant levels are commonly 10 to 100 times greater than plasma levels

Answer 10

True

Tissue cyclic antide- pressant levels are commonly 10 to 100 times greater than plasma levels

Question 11

Life-threatening symptoms usually occur with ingestions of ____ in adults, and fatalities are commonly associated with ingestions of ____

Answer 11

> 10mg/kg in adults

>1gram

Question 12

The most potent sodium channel blocker among the cyclic antidepressants and is able to precipitate severe cardiotoxicity

Answer 12

Desipramine

Question 13

Historically been associated with greater toxicity than other cyclic antidepressants, especially in regard to causing seizures

Answer 13

• Amoxapine

- Maprotiline

Question 14

Therapeutic level of cyclic antidepressants

Answer 14

75 to 300 nanograms/mL (300 - 1000nmol/L

Question 15

Most common symptom reported after cyclic antidepressant exposure

Answer 15

Altered mental status

Question 16

Most frequent dysrhythmia noted in cyclic antidepressant toxicity

Answer 16

Sinus tachycardia

Question 17

How many hours will you see a serious toxicity after ingestion of cyclic antidepressants

Answer 17

6 hours

Question 18

The only cyclic antidepressant that produce seizure with no other signs of toxicity

Answer 18

Amoxapine

Question 19

The risk of seizures increases if the QRS complex is ____, and ventricular dysrhythmias are more common if the QRS duration is ____

Answer 19

The risk of seizures increases if the QRS complex is >100 milliseconds, and ventricular dysrhythmias are more common if the QRS duration is >160 milliseconds

Question 20

It is given with patient after cyclic antidepressants. Can give if patients are awake, have a patent airway, and arrive within 1 hour of ingestion

Answer 20

Give a single 1 gram/kg dose of activated charcoal PO

Question 21

Used to treat cardiac conduction abnormalities, ventricular dysrhythmias, or hypotension refractory to IV fluid in tricyclic antidepressants

Answer 21

Administer sodium bicarbonate as an initial IV bolus of 1 to 2 mEq/kg. Until blood pH between 7.50 and 7.55

Question 22

Sodium bicarbonate continuous infusions dosage

Answer 22

Sodium bicarbonate can be administered as 150 mEq added to 1 L of 5% dextrose in water and infused IV at a rate of 2 to 3 mL/kg per hour

Question 23

Altered level of consciousness in tricyclic antidepressants is cause by?

Answer 23

Antagonism of postsynaptic muscarinic, histaminic and a-adrenergic receptors

Question 24

Treatment of Cyclic antidepressant overdose

Answer 24

• Activated charcoal
• Sodium Bicarbonate for hypotension
• Benzodiazapine for seizure
• MgSO4 2gm

Question 25

Anticonvulsants of choice to stop seizure activity in cyclic antidepressant

Answer 25

Benzodiazepines

Phenobarbital 10-15mg/kf

Question 26

Major side effect of IV phenobaarbital administration

Answer 26

Hypotension

Question 27

True or False

Phenytoin, sodium bicarbonate, and physostigmine do not stop cyclic antidepressant–induced seizures

Answer 27

True

Question 28

Why Norepinephrine and Epinephrine are effective vasopressors in cyclic antidepressants?

Answer 28

Because it directly compete with the cyclic antidepressants at the a-adrenergic receptors

Question 29

It is might be effective in patients with refractory cyclic antidepressant–induced hypotension

Answer 29

Glucagon 1mg IV

Question 30

Which medications are contraindicated in the treatment of cyclic antidepressant induced dysrhythmias

Answer 30

• Class I antiarrhytmia
• Class III antiarrhytmia
• Beta blockers
• Calcium channel blocker