test 5 benzodiazepines, benzo reversal, and barbiturates

Question 1

How Benzodiazepines work

Answer 1

• Target GABAA receptors
• Binding triggers opening of the central ion channel
• Influx of chloride ions
• Hyperpolarization of the neuron from the Cl- entry making it more difficult to depolarize reducing neural excitablilty
• Decreased neurotransmission by inhibiting the formation of action potentials
- binding of GABA is enhanced by benzodiazepine, resulting in a greater entry of Cl-
- Benzodiazepines increase the frequency of channel openings produced by GABA

Question 2

Benzodiazepine Actions

Answer 2

• Reduction of anxiety
• Sedation/Hypnosis
• Anterograde amnesia
  * Temporary impairment of memory
  * Ability to learn and form new memories is also impaired
• Anticonvulsant
• Muscle relaxant

Question 3

Benzodiazepine Uses

Answer 3

• Anesthesia premedication to reduce anxiety
• Provide conscious sedation
• Anxiety disorders
• Sleep disorders
• Seizures
• Muscular disorders

Question 4

Diazepam (Valium) duration of action

Answer 4

• 1-4 days

Question 5

Lorazepam (Ativan) duration of action

Answer 5

• 10-20 hours

Question 6

Midazolam (Versed) duration of action

Answer 6

• 2-6 hours

Question 7

Characteristics of Benzodiazepines

Answer 7

• Lipophilic- penetrate into CNS
• Psychological and physical dependence can develop- controlled substances
• Relatively safe- Lethal dose 1000x greater than therapeutic dose

Question 8

Flumazenil

Answer 8

• Benzodiazepine Reversal
• Potent COMPETITIVE benzodiazepine receptor blocker
• Reverses the effects of benzodiazepines on CNS
• Used post operatively

Question 9

Barbiturates

Answer 9

• Former mainstay for sedation or to induce sleep
• Largely replaced by benzodiazepines
• Potentiate GABA action on chloride entry into the neuron prolong channel opening
• Can block excitatory glutamate receptors

Question 10

Barbiturate actions

Answer 10

• Depression of CNS
  * Low doses: sedation
  * Higher doses: hypnosis followed by anesthesia, then coma and death
• Respiratory depression

Question 11

Barbiturate Uses

Answer 11

• Anesthesia- NOT ANYMORE!
• During circulatory arrest to “protect the brain” – NOT SO MUCH ANYMORE.
• Still listed in massive air embolism protocols
• Anticonvulsants
  * Long term management of seizures if all other therapies have failed
• Sedative/Hypnotic
  * Relieve anxiety or nervous tension
  * Sedative to assist in migraine headache management