Barbiturates Part 2 Flashcards
What is the only drug that increases metabolic O2 requirements?
Ketamine
What drug increases the demand of oxygen but decreases the supply of blood to the brain?
Ketamine
What is not good to give for global ischemia but is great for focal ischemia?
thiopental
Use barbiturates to temporarily tolerate ischemia.
Thiopental is great for certain focal ischemia situations. Name 3.
carotid endarterectomy
thoracic aneurysm resection
cerebral aneurysm clipping
What are the effects of thiopental? (4)
decrease systolic BP
increase HR
histamine release
heat loss due to vasodilation
What are other side effects of thiopental? (3)
VLC
ventilation
laryngospasm
CMRO2 decreased up to 55%
Reasons why we don’t use thiopental: (8)
- Benzo’s have a more specific site of action
- Lower therapeutic index than benzos
- Result in tolerance more frequently than benzo’s
- High incidence of abuse
- High risk for drug interactions
- Paradoxical excitement instead of sedation
- No skeletal muscle relaxation
- HANGOVER
What is a direct contraindication for using thiopental?
Acute Intermittent Porphyria
Patients with porphyria have a deficiency of certain enzymes needed for this process. This causes abnormal amounts of porphyrins or related chemicals to build up in the body.
The more thiopental you use, the more half life there is. The longer it takes to wear off. True or false?
true
What drug has a longer half life than thiopental after prolonged infusion?
diazepam
valium
What are the symptoms of porphyria?
- malaise
- insomnia
- Anxiety or restlessness
- Severe abdominal pain
- Constipation
- Vomiting
- Diarrhea
Why are barbiturates bad for those that have porphyria?
Thiopental may precipitate porphyria due to hepatic enzyme induction in susceptible patients, and hence
it should be avoided
Can we use benzos and propofol safely in porphyria?
Yes
What drug is more lipid soluble than thiopental?
methohexital
Brevital
Methohexital (Brevital) IV induction dose:
Rectal dose:
1-1.5 mg/kg
20-30 mg/kg
