Cyclic Antidepressant OD - Toxicology

Question 1

True or false, the following are examples of cyclic antidepressants:
Anafranil (clomipramine)
Asendin (amoxapine)
Elavil (amitriptyline)
Norpramin (desipramine)
Pamelor (nortriptyline)

Answer 1

True

Question 2

If a patient has overdosed on cyclic antidepressants and is hypotensive, in a wide complex tachycardia, has a QRS <0.12s or is seizing what’s the first drug to administer? Why?

Answer 2

Sodium bicarbonate 1-2 mEq/kg q. 5 min prn (may repeat x1 for a map <65 or wide complex tachycardia)
Note: stop sodium bicarb boluses if QRS <0.12s or pH >7.55
Note: if seizures refractory to sodium bicarb tx concurrently with seizure medical directive
Why? Because TCAs are sodium-channel blockers

Question 3

Due to the dysrhythmias associated with cyclic antidepressant ODs, what does the MDSO list as the treatment for torsades de pointes?

Answer 3

Magnesium Sulfate
2g over 15 min

Question 4

What therapy may be considered in a TCA overdose to remove some of the lipophilic drug from the bloodstream?

Answer 4

Intralipid (20%) therapy
1.4 mL/kg over 5 min, repeat x1, then
.25 mL/kg infusion, max total dose 12 mL/kg

Question 5

What agent should be used in a TCA overdose with hypotension refractory to an NS bolus and sodium bicarbonate?

Answer 5

Norepinephrine, of course!