Pharmacology of anxiolytic drugs

Question 1

Name the 6 classes of drug used to treat anxiety?

Answer 1

Barbiturates (DODGE)
Benzos
antidepressants 
Buspirone
Pregablin 
B-blockers (propranolol)

Question 2

Benzodiazepines

• give 4 examples
• effects?
• MOA?
• clinical uses?
• adverse effects?

Answer 2

-Midazolam
Lorazepam
Diazepam
oxazepam

-reduces anxiety and aggression
hypnosis/sedation
muscle relaxation
anticonvulsant effect

-increase GABA mediated ihbition so Cl can’t be transported through the GABAa receptors and depolarisation does not occur

-acute anxiety 
hypnosis
alcohol withdrawal
Mania, delirium 
status epilepticus

-fairly safe in overdose and have an antagonist (Flumazenil)
paradoxical aggression
impaired coordination & anterograde amnesia
tolerance and dependence

Question 3

withdrawal symptoms (benzos)

• examples? (7)
• cause?
• what is the correct way to withdraw benzos?

Answer 3

-rapid withdrawal of benzos can give confusion, toxic psychosis and convulsions
+ insomnia, anxiety, loss of appetite, tremor

-neuro adaption of the GABA response
chronic treatment causes reduced response to GABA. withdrawal results in anxiety/convulsions maybe due to reduced density of BZ receptors

• 1.transfer patient to equivalent dose of diazepam to take at night
  2. reduces does every 2-4 wks in steps of 2-2.5mg, if symptoms then maintain does till symptoms resolve
  3. reduce dose further if necessary in small steps
  4. stop completely, can take from 4 months- yr

Question 4

Antidepressants in anxiety 
-in what disorders or the following groups of ADs used?
SSRIs
Tricyclics
venlafaxine
moclobemide

Answer 4

SSRIs
panic disorder, OCD, PTSD, phobias
GAD (escitalopram, paroxetine)

TCAs
OCD, 2nd line panic disorder (clomipramine, imipramine)

venlafaxine
GAD

moclobemide
social anxiety disorder

Question 5

What is given if unresponsive to other treatment?

Answer 5

Pregabalin

Ca2+ channel blocker, GABA enhancer

Question 6

When would Beta blockers be used?

Answer 6

with somatic symptoms e.g. palpitation, tremor

Question 7

Buspirone MOA?

Answer 7

5-HT 1A receptor partial agonist, presynaptic dopamine antagonist at the D2, D3 andD4 receptors, partial alpha receptor agonist, overall suppress seratonergic activity while noradrenergic and dopaminergic cell firing is enhanced
BUT messy, lots of SEs