Benzos, and Barbiturates factoids

Question 1

Compared to thiopental, methohexital has a ___ duration of action. The duration of thiopental is:___. The duration of methohexital is: ____

Answer 1

shorter
Thiopental: 10-30 min
Metho: 5-7 min.

Question 2

What is a clinical use for barbs?

Answer 2

To reduce ICP. Barbs reduce CMRO2 which decreases CBF and ICP.
Also used in Propofol shortages

Question 3

What are the effects of barbs on CV, resp, liver, and kidney?

Answer 3

CV: Decreased BP- vasodilation, decreased VR
Resp: Dose dependent depression especially if used in combo. with other resp depressants.
Liver: Enzyme inducers (increases metab. of other drugs)
Kidney: Modest decrease in blood flow from low BP

Question 4

Do you see skeletal muscle relaxation with barbs?

Answer 4

Nope

Question 5

What are the problems associated with intra arterial injection of barbs?

Answer 5

Arterial spasm, thrombosis, distal limb ischemia

Question 6

What is the recommended treatment for intra arterial injection of barbs? (2 of them)

Answer 6

1. arterial injection of lidocaine for analgesia and vasodilation
2. brachial plexus block (regional anesthesia) causing analgesia and vasodilation for longer duration

Question 7

Five principle pharmacological properties of benzos

Answer 7

sedation, anxiolysis, anticonvulsant, spinal cord mediated skeletal muscle relaxation, anterograde amnesia (minimal retrograde)

Question 8

True or false, benzos provide analgesia and have antiemetic properties.

Answer 8

False

Question 9

A benefit to benzos wrt sedation, anxiolysis, and amnesia is that:

Answer 9

The amnesia and anxiolysis lasts longer than the sedation

Question 10

What are the CV and respiratory effects of benzos?

Answer 10

Minimal CV depression. Minimal resp. depression alone, but potentiate resp depression of other drugs used in combo with benzo. i.e. fentanyl and versed cause increased respiratory depression.

Question 11

Midazolam: Induction dose and duration of action

Answer 11

0.1-0.3 mg/kg IV, 15-20 min

Question 12

Compared to prop, ketamine, and etomidate, midaz has a ___ context sensitive half time

Answer 12

Longer

Question 13

Compared to midaz, prop, ketamine, and etomidate, thiopental has a ___ context sensitive half time

Answer 13

Much longer. Even after short infusions of the medication the context sensitive half time is significantly longer and there is a sharp increase after 1 hour infusion duration

Question 14

What is the mechanism of action of benzos?

Answer 14

Facilitate the mechanism of GABA by binding to an allosteric site and increasing the receptors affinity for endogenous GABA.

Question 15

Does midaz cross the BBB easily? What does that mean for it’s lipid solubility vs water solubility?

Answer 15

Easily crosses means it’s highly lipid soluble.

Question 16

What is the reversal agent for benzos and what is it’s duration of action?

Answer 16

Flumazenil- 30-60 min.

Question 17

Induction dose of Thiopental

Answer 17

3-6 mg/kg IV

Question 18

Induction dose of Methohexital

Answer 18

1-2mg/kg IV

25 mg/kg PR for children

Question 19

Induction dose of diazepam

Answer 19

0.3-0.6 mg/kg IV

Question 20

What is an undesirable effect of thiopental? Both thiopental and methohexital?

Answer 20

Histamine release with thiopental; hangover feeling after administration of either