Tricyclic Overdose/Poisoning Flashcards
How often are tricyclic antidepressants (TCAs) used in overdose.
Very frequently.
What is the cause of the high mortality and morbidity associated with TCA overdose. (3)
Due to their sodium channel blocking, anticholinergic and alpha-adrenoceptor blocking effects.
What are the features of TCA poisoning. (2)
Anticholinergic effects.
Life threatening complications are frequent.
What are the life threatening effects of TCA poisoning. (4)
Convulsions.
Coma.
Arrhythmias (ventricular tachycardia, ventricular fibrillation, heart block).
Hypotension.
What is the cause of hypotension in TCA poisoning. (2)
From inappropriate vasodilatation or impaired myocardial contractility.
What are the cardiovascular anticholinergic effects seen in TCA poisoning. (2)
Tachycardia.
Hypotension.
What are the CNS anticholinergic effects seen in TCA poisoning. (4)
Confusion.
Hallucinations.
Sedation.
Increased reflexes and extensor plantar responses.
What are the muscular anticholinergic effects seen in TCA poisoning.
Myoclonus.
What is the anticholinergic effect on the temperature seen in TCA poisoning.
Fever.
What are the anticholinergic effects on the eyes seen in TCA poisoning. (2)
Diplopia.
Mydriasis.
What are the abdominal anticholinergic effects seen in TCA poisoning. (3)
Ileus.
Palpable bladder (urinary retention).
Diarrhoea.
What is the anticholinergic effect on the mouth often seen in TCA poising.
Dry mouth.
What is the anticholinergic effect on the skin often seen in TCA poisoning. (3)
Flushing.
Hot
Dry.
What is the main MOA of TCAs.
They block the reuptake of noradrenaline (norepinephrine) into peripheral and intracerebral neurones.
What are the features of severe TCA poisoning. (6)
Coma. Divergent strabismus. Convulsions. Plantal, oculocephalic and oculovestibular reflexes may be temporarily abolished. Metabolic acidosis. Cardiorespiratory depression.
