Anti-anxiety Drugs

Question 1

What class of drugs do we use to treat anxiety?

Answer 1

Benzodiazepines.
- commonly used as anxiolytics & hypnotics

(Also used as sedative and amnestic)

Question 2

List out the benzodiazepine drugs and their duration of action.

Answer 2

Short acting (4h)
1. Midazolam

Intermediate acting (8h)
2. Lorazepam
3. Alprazolam

Long acting (1day)
4. Diazepam

- duration of action is dose-dependent

Question 3

Simply put, what do Benzodiazepines do? (Pharmacodynamics)

Answer 3

• potentiates GABA actions by increasing the frequency of channel opening induced by GABA
• GABA dependent, wont work if theres no GABA
• allows more Cl- into cell
• cell becomes more negative/hyperpolarised=> less chance of getting depolarised

Question 4

What is the PK/absorption of benzodiazepines?

Answer 4

1. Oral: fast onset (0.5-1hr)
2. IV: immediate
3. IM: unpredictable

Question 5

List out the therapeutic uses of Benzodiazepines: (what its used to treat)

Answer 5

1. Tx for anxiety and insomnia
2. Epilepsy (iv: diazepam, lorazepam)
3. Muscle relaxant
4. Premedication for sedation as part of balanced anaesthesia (iv: diazepam, lorazepam, midazolam)
5. Alcohol withdrawal

Question 6

List out the adverse effects of Benzodiazepines:

Answer 6

1. CNS: drowsiness, diminished motor skills, increased reaction time
2. CNS: anterograde amnesia, memory disturbances particularly profound aft IV sedation
3. Paradoxical effects: hallucination, hypomanic behaviour, irritability
   - prof gave example of patients who scream at frontdesk cuz they have memory loss + irritable or like in the past when a doctor was wrongly convicted cuz the patient thought he sexually harassed her
   - must make sure patient dont take drug then drive later get into accident -> ure fault for not warning
4. CVS: reduced BP, if given rapidly via IV, may cause cardiac arrest
   - postural hypotension
   - some patients nvr wake up from GA, must know how to resuscitate!!
5. Tolerance, dependence & withdrawal

Question 7

What are the CNS adverse effects of taking Benzodiazepines?

Answer 7

• dose-related drowsiness
• diminished motor skills
• increased reaction time
• anterograde amnesia (memory disturbances esp aft IV)

+ paradoxical effects
- garrulousness (talkative)
- irritability
- hallucination
- hypomanic behaviour

Question 8

What are the CVS adverse effects of taking Benzodiazepines?

Answer 8

• decreased BP when given rapidly (may cause cardiac effects => cardiac arrest)