Induction Meds: Methohexital (Oxybarbiturates)

Question 1

At a normal pH _______% of methohexital is non-ionized.

At a normal pH ____% of sodium pentothal is non-ionized.

What does this mean in regards to induction for comparing these drugs?

Answer 1

• 76% non-ionized Methohexital
• 61% non-ionized Sodium Pentothal
• Methohexital for induction has a faster metabolism and recovery due to its increased lipid-solubility.

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Question 2

Which barbiturate causes excitatory symptoms like myoclonus and hiccups?

Answer 2

Methohexital

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Question 3

How would methohexital infusions differ from induction?

Answer 3

Very lipid-soluble so:

• Drug persists from infusion but clears quickly from induction.

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Question 4

What is the IV methohexital dose?

Answer 4

1.5 mg/kg IV

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Question 5

What is the seizure profile of methohexital?

Answer 5

Can induce seizures but is better than etomidate or when used with ECT.

1. Continuous infusions induce post-op seizures in ⅓ of patients.
2. Seizures are induced in patients undergoing temporal lobe resection.
3. Seizure duration reduced 35-45% in ECT patients vs etomidate.

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Question 6

What is per rectum dose of Methohexital?

Answer 6

20 - 30 mg/kg PR

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