Toxicology with Erin and Dr. Clancy - TCAs

Question 1

TCA ingestion

Answer 1

main things - decontamination - with charcoal if there is an airway issue/oversedation - best to intubate
EKG - to look for QRS prolongation - this would be an indication to give Na Bicarb

Question 2

With patient who has obvious TCA intoxication

Answer 2

Start Bicarb drip - 3 amps ( 50 Meq of bicarb in 1 amp) in a L of D5 W - this is equavalent of NS - 20cc /kg bolus - over an hour

Question 3

Disadvantages of bicarb

Answer 3

there are case reports of pulm edema - you must continue to reassess

Question 4

TCA tabs - toxicity in children

Answer 4

1-2 tablets could kill a child

Question 5

TCA antidote

Answer 5

No antidote

Question 6

TCA examples

Answer 6

Amitiptaline, clomipramine, etc.

Question 7

TCA use

Answer 7

depression, peripharal neuropathy, enuresis

Question 8

Toxicity dose

Answer 8

10-20mg/kg

Question 9

Pathophys of TCA

Answer 9

inhibits uptake of NE and 5HT -
Blocks Na channels - decreased conduction velocity - widens QRS - similar to brugada
Antgonises alpha 1 and directly results in mycocardial depression - can also antagonize Ach

Can cause delayed gastric emptying

Question 10

TCA drug levels - helpful true or false

Answer 10

Not helpful

Question 11

EKG changes with TCA

Answer 11

QRS prolongation (>100, 34% would have seizures and 14% would go on to have Vent arrhythmias) - RBBB, Brugada pattern, QT prolongation

When it gets bad - looks like hyperkalemia

rsR prime in AVR ( does not count in V1)

Question 12

Treatment of TCA toxicity

Answer 12

Charcoal - can be given due to delayed gastric emptying -
Na bicarb given if QRS >100 \
1-2 mEq/kg - may repeat every 3-5 minutes

Goal ph 7.5- 7.55- avoid acidosis

Question 13

Bicarb rolen in TCA toxicity

Answer 13

Not for elimination in this case - as TCAs are metabolized for liver -( unlike salicylates) - bicarb is used to get TCA off myocardium

Question 14

TCA arrhythmias - Rx

Answer 14

Bicarb - Lidocaine, mag

Question 15

Life threatening TCA overdose

Answer 15

Consider lipids - as a lipid sink

Hemodialysis not effective as there is a huge volume of distribution

Question 16

Hypotension with TCAs

Answer 16

Fluids and pressors such as NE

Question 17

1 pill can kill

Answer 17

sulfonyl ureas
Ca channel blockers 
TCAs
Digoxin, 
oil of wintergreen 
B blockers