Chapter 177: Cyclic Antidepressants Flashcards
(30 cards)
It is a muscle relaxant that is almost structurally identical to amitriptyline but lacks antidepressant activity, and serious toxicity from overdose is rare?
Cyclobenzaprine
It is a tetracyclic (also termed a heterocyclic), with a four-ring central structure plus a side chain?
Maprotiline
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
True
Tertiary amines are generally more potent in blocking reptake of serotonin compared to blocking reuptake of norepinephrine
Sample of secondary amines cyclic antidepressants
- Desipramine
- Nortriptyline
- Protriptyline
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
Amoxapine
The only antidepressant that has antipsychotic effects and can produce seizure with minimal warning and normal QRS complex
Amoxapine
The most important factor contributing to patient mortality in Cyclic antidepressant
Cardiotoxicity
Cardiac conduction abnormalities occur during cyclic antidepressant poisoning because inhibition of?
Fast sodium channels in the His-Purkinje system and myocardium decreases conduction velocity,
The effect seen in ECG in patient taking cyclic antidepressants
QT interval prolongation which is more pronounced at slow heart rate
True or False
Tissue cyclic antide-pressant levels are commonly 10 to 100 times greater than plasma levels
True
Tissue cyclic antide- pressant levels are commonly 10 to 100 times greater than plasma levels
Life-threatening symptoms usually occur with ingestions of ____ in adults, and fatalities are commonly associated with ingestions of ____
> 10mg/kg in adults
>1gram
The most potent sodium channel blocker among the cyclic antidepressants and is able to precipitate severe cardiotoxicity
Desipramine
Historically been associated with greater toxicity than other cyclic antidepressants, especially in regard to causing seizures
- Amoxapine
- Maprotiline
Therapeutic level of cyclic antidepressants
75 to 300 nanograms/mL (300 - 1000nmol/L
Most common symptom reported after cyclic antidepressant exposure
Altered mental status
Most frequent dysrhythmia noted in cyclic antidepressant toxicity
Sinus tachycardia
How many hours will you see a serious toxicity after ingestion of cyclic antidepressants
6 hours
The only cyclic antidepressant that produce seizure with no other signs of toxicity
Amoxapine
The risk of seizures increases if the QRS complex is ____, and ventricular dysrhythmias are more common if the QRS duration is ____
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
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
Give a single 1 gram/kg dose of activated charcoal PO
Used to treat cardiac conduction abnormalities, ventricular dysrhythmias, or hypotension refractory to IV fluid in tricyclic antidepressants
Administer sodium bicarbonate as an initial IV bolus of 1 to 2 mEq/kg. Until blood pH between 7.50 and 7.55
Sodium bicarbonate continuous infusions dosage
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
Altered level of consciousness in tricyclic antidepressants is cause by?
Antagonism of postsynaptic muscarinic, histaminic and a-adrenergic receptors
Treatment of Cyclic antidepressant overdose
- Activated charcoal
- Sodium Bicarbonate for hypotension
- Benzodiazapine for seizure
- MgSO4 2gm
