Antianxiety agents

Question 1

What are the signs and symptoms of anxiety?

Answer 1

Heart rate increase
RR increase, hyperventilation, respiratory alkalosis, dizziness
GI pain, butterflies, constipation/diarrhoea
More frequent urination
Skin cold
Muscles tense

Question 2

What are benzodiazepines?

Answer 2

Commonly used anxiolytics and hypnotics

Midazolam is short acting
Lorazepam, alprazolam are intermediate acting
Diazepam is long acting

Question 3

How do benzodiazepines work?

Answer 3

They potentiate GABA actions via specific benzodiazepine sites in the CNS, increasing the frequency of inhibitory chloride channels opening, making neurons less likely to fire

GABA dependent

Question 4

How does phenobarbital differ from benzodiazepines?

Answer 4

Phenobarbital causes continuous opening of chloride channels, independent of GABA, can be fatal with overdose

Benzodiazepines are GABA dependent, and are therefore safer

Question 5

What are the onsets of benzodiazepines?

Answer 5

Oral has rapid onset of 0.5-1h, crosses BBB rapidly

Midazolam, lorazepam, diazepam are administered parenterally, IV onset is immediate but IM is unpredictable

Question 6

What is the pathway of biotransformation of diazepam?

Answer 6

Diazepam –> Nordazepam –> Oxazepam –> Glucuronidation

Question 7

What are the clinical uses of benzodiazepines?

Answer 7

Treatment for anxiety and insomnia

Emergency treatment for status epilepticus (give IV diazepam/lorazepam)

Muscle relaxant

Premedication for sedation as part of balanced anesthesia

Alcohol withdrawal