Barbs

Question 1

What is the MOA of Thiopental?

Answer 1

• decrease the rate at which GABA dissociates from the receptor
• Increase duration of GABA activation
• Increases chloride conductance- hyperpolarizes the cell
• Decreases neuronal transmission
• Decreases sympathetic ganglia transmission- hypotension
• decrease postsynaptic membrane sensitivity to AcH- muscle relaxation
• Decrease RAS- sleep

Question 2

What are the pharmacokinetics of thiopental?

Answer 2

• 70% protein bound
• highly lipid soluble
• crosses BBB
• onset-fast
• rapid redistribution in 2-4 minutes
• E1/2t 11.6 hours (hangover effect)
• metabolized by CYP450 with some extrahepatic metabolism and renal excretion
• Induces CYP450 which increases metabolism of Dilantin, anticoagulants, Vitamin K, TCAs, steroids.
  *

Question 3

What are the side effects of thiopental?

Answer 3

• decreased CBF, ICP, & CMRO2
• isoelectric EEG
• decreased IOP
• decreased BP, cardiac depression
• respiratory depression
• HISTAMINE release
• decreased laryngeal cough reflexes
• Increased heme production- bad in porphyria
• N/V
• anaphylaxis with high mortality

Question 4

What are the contraindications to thiopental?

Answer 4

• porphyria
• asthma
• pregnancy
• watch in drugs metabolized by CYP450
  *

Question 5

What is the dose of thiopental?

Answer 5

3-5mg/kg IV

Question 6

What is the drug class/ chemical description of thiopental?

Answer 6

• barbiturate
• thiobarbiturate with sulfur at carbon #2