Anticonvulsant toxicity - CBZ

Question 1

Describe CBZ’s absorption characteristics

Answer 1

Slow, unpredictable

Question 2

tmax of CBZ in normal doses?

Answer 2

4-8h

Question 3

tmax of CBZ in overdose?

Answer 3

24+ h

Question 4

Plasma protein binding of CBZ (percentage)?

Answer 4

~76%

Question 5

CBZ is metabolized by…

Answer 5

CYP3A4

Question 6

How is CBZ’s metabolite excreted (trans-CBZ-diol)?

Answer 6

renally

Question 7

What’s unique about CBZ’s metabolism?

Answer 7

CBZ autoinduces its own metabolism

Question 8

T or F: CBZ’s half life decreases as dosing increases

Answer 8

T (due to autoinduction)

Question 9

Normal therapeutic plasma levels of CBZ?

Answer 9

16-48 µmol/L

Question 10

Major neurologic sx’s of CBZ overdose?

Answer 10

Ataxia and seizure

Question 11

resp sx’s of CBZ tox?

Answer 11

Resp depression, apnea

Question 12

CV sx’s of CBZ tox?

Answer 12

sinus tachycardia, hypotn, ECG abnormalities

Question 13

How can CBZ tox cause hyponatremia?

Answer 13

SIADH

Question 14

Best way to decontaminate during CBZ tox?

Answer 14

Single dose activated charcoal (it binds!)

Question 15

How long do you have before SDAC becomes less effective?

Answer 15

1-2h post-ingestion

Question 16

Major electrolyte that should be measured during CBZ toxicity?

Answer 16

Na

Question 17

T or F: MDAC is NOT recommended for CBZ tox.

Answer 17

F

Question 18

When is MDAC recommended for CBZ tox?

Answer 18

If tox is SEVERE

Question 19

When should hemodialysis be used for CBZ tox?

Answer 19

refractory multiple seizures, life-threatening dysrhythmias

Question 20

CBZ decontamination methods:

Answer 20

SDAC

Question 21

CBZ elimination methods:

Answer 21

MDAC, hemodialysis

Question 22

hemodialysis for CBZ tox should be continued until…

Answer 22

clinical improvement, [CBZ] < 42 µmol/L

Question 23

CBZ tox antidote.

Answer 23

None