(TCAs) ANTIDEPRESSANTS

• Amitriptyline

• Nortriptyline

• Desipramine

• Imipramine

• Doxepin

• Nordoxepin

• Dothiepin

• Clomipramine.

TRICYCLIC ANTIDEPRESSANTS (TCAS)

Blockade of :

• peripheral alpha-adrenergic,

• muscarinic,

• histamine,

• serotonin receptors

• Fast sodium channels

• GABA receptor

• Potassium channel antagonism

TCA Mechanism of Toxicity

hypotension

Blockade of Alpha-adrenergic receptor can cause

anticholinergic toxicity

Blockade of Muscarinic receptor can cause signs of

altered mental status and CNS excitation

Blockade of histamine receptors can cause

exert membrane stabilizing effects (quinidine-like)

Blockade of Fast sodium channels

seizure

Blockade of GABA receptor can cause

QT prolongation

Blockade of Potassium channel antagonism can cause

10–20 mg/kg

TCA ingestion of _______: potentially life threatening.

Procainamide or other type la or Ic antiarrhythmic agents

can aggravate cardiotoxicity

neuromuscular blocker

Use of ________if seizures persist after the giving anticonvulsants

• Sodium bicarbonate 1-2 mEq/kg IV

• Lidocaine

• IV lipid emulsion therapy

• Physostigmine

SPECIFIC ANTIDOTE:

Lidocaine

if the cardiotoxicity persists after treatment with sodium bicarbonate

IV lipid emulsion therapy

for severe clomipramine overdose

Physostigmine

• was used as an antidote in the past,

• can aggravate conduction disturbances, causing asystole;

• further impair myocardial contractility, worsening hypotension; and contribute to seizures

activated charcoal

Gl decontamination by__________should only be done if conditions are appropriate and the airway is protected

Gastric lavage is not necessary