L15 Tricyclic antidepressants toxicology

 L15 Tricyclic antidepressants toxicology

داتا المحاضره


بالنسبة ل Na channel 

1- Na ميدخلش : 

وهو المسؤول عن ال depolarization ف هيعمل 3C 

 *Cardiac toxicity >> علي هيئه 

*Conduction delay 

*- ve Chronotropic effect >> decrease heart rate 

2- Ca ميدخلش: 

مسؤول عن ال contractility ف هيحصل 

depressed contractility = -ve inotropic effect 

3- K ميخرجش >> cardiac toxicity

جزء البوتاسيوم بس اللي محتاج تعديل

وفيه توضيح للي هي شارحها وكدة

 ✨دا توضيح للشرح

بالنسبه لجزئية ال 
Intravenous lipid emulsion (ILE) therapy : 

قلنا إنها بتوفر

 free fatty acids to improve myocardial activity 

في theory اضافيه وهي ال most prevalent

ان الادويه ال lipid soluble زي ال TCA بتحب تدخل ال tissues عشان ال membrane عباره عن lipid وهي بتدوب فيه 

ف انت لو خليت الوسط بره ( الدم ) فيه lipid ف هي هتخرج من ال tissue للدم عشان بقي وسط مناسب وساعتها هتقدر تعمل dialysis مثلا 

( The most prevalent of several theories describing the purported mechanism of ILE is the ‘‘lipid sink’’ theory. According to this theory, the administration of lipid reduces the volume of distribution of the drug in question by pulling lipid soluble drugs out of the periphery and into the vascular compartment.)


1-The common signs of TCAs toxicity are the following except

a) Prolonged QRS complex

b) Ventricular tachycardia

c) Refractory hypertension

d) Altered mental status

answer (c)

2-Toxicity of tricyclic antidepressant induces

a) Bradycardia

b) Convulsion

c) Excessive lacrimation 

d) Hypothermia

answer (b)

3-The signs of TCAs toxicity include all of the following except 

a) Coma and seizures

b) Cardiac conduction delays. Supra ventricular and ventricular tachycardia

c) Hypertension and hypothermia 

d) Aspiration pneumonia and respiratory depression

answer (c)

4-Patients with tricyclic antidepressant toxicity may present with:

 A) Pupil dilatation  

 B) Pupillary constriction

 C) Midsized pupils  

 D) All of the above

Answer (d)

5-A patient has an overdose of a tri-cyclic antidepressant compound. What is NOT a characteristic ECG changes

(A) Bradycardia

(B) Tall R wave in V1

(C) narrowing of QRS

(D) S wave in 1, aVL

(E) Prolongation of QT interval

answer (c)

6- If sodium bicarbonate therapy is ineffective, which of the following anti-dysrhythmics may be used to treat  ventricular dysrhythmias associated with TCA overdose?

A. β-blockers  

B. Calcium channel blockers  

C. Phenytoin  

D. Lignocaine

E. Class IA or IC anti-dysrhythmics

answer (d)

7- The best predictor of serious toxicity in TCA poisoning is:  

a) drug plasma levels  

b) GCS less than 8  

c) estimates of ingested drug dose  

d) rightward deviation of the QRS vector  

e) QRS duration of >100msec

answer (e)

True & False:

  1. Phenytoin is indicated as anticonvulsant in case of TCAs toxicity. (F)

  1. In the treatment of TCAs toxicity, administration of phenytoin, flumazenil and physiostagmine are contraindicated. (T)

  1. Flumazenil is indicated for seizures in TCA toxicity. (F)

  1. Forced diuresis and dialysis are effective in treatment of TCA toxicity. (F)

  1. Induction of emesis is contraindicated in cases of TCA toxicity. (T)