Pharmacology of Anxiolytic Drugs Flashcards
Drugs used to treat anxiety?
Benzodiazepines ADs Buspirone Pregabalin Propanolol
Which area of the brain predominates in fear based anxiety (panic, phobia)?
Amygdala centred circuit
Which area predominantes in worry based anxiety (anxiety, apprehension, obsessions)?
Cortico-striatal thalamic-cortical circuit
What is the function of the amygdala in fear?
Integrates sensory and cognitive info
Which area of the brain mediates avoidance in fear (fight/flight)?
Periaqueductal gray area of brainstem
Which area of the brain mediates the autonomic output in fear (incr BP and HR)?
Locus coeruleus
Which area of the brain mediates the re-experiencing of traumatic memories?
Hippocampus
Neurotransmitters involved in amygdala centred circuits?
Serotonin GABA Glutamate CRF NA Voltage gated ion channels
Action of GABA in fear?
Reduced activity of neurones in amygdala and CSTC circuit
Which drug`s for anxiety target GABA-A receptors?
Benzodiazepines; enhance GABA action
Also alcohol and barbiturates
Which ion channel is affected when BDZ binds to GABA-A receptors?
Chloride channel via positive allosteric modulation
Which anaesthetic agents act on the GABA receptors?
Propofol
Steroids
Halothane
Pharmacological effects of BZD
Reduce anxiety and aggression Hypnosis/ sedation Muscle relaxation Anticonvulsant effect Anterograde amnesia
Clinical uses of BZD
Acute treatment of extreme anxiety Hypnosis Alcohol withdrawal Mania Delirium Rapid tranquilisation Premedication before surgery Status epilepticus
Problems with BZD?
Paradoxical aggression
Anterograde amnesia and impaired coordination
Tolerance and dependence
Symptoms of BZD withdrawal?
Abdo cramps Increased anxiety Blurred vision Depression Insomnia, nightmares Dizziness Headaches Inability to concentrate N+V Restlessness Sensory sensitivity
Symptoms of raid withdrawal of BZD
Confusion Psychosis Convulsions Tachy Sweating Hypertx Agitation Tremor
How to withdrawal BZDs?
Transfer patient to daily dose of diazepam/ chlordiazepoxide
Reduce dose every 2-3 weeks in steps o 2- 2.5 mg
Reduce dose further
Stop completely
What is the key nT that innervates the amygdala?
Serotonin
How do ADs treat anxiety?
SSRIs increase extracellular serotonin
Neuroadaptive changes; expression of receptors for serotonin and/or glucocorticoids that depend upon sustained exposure to high extracellular concs of serotonin
Increased neurosteroid synthesis
For what anxiety disorders are SSRIs prescribed?
Panic, OCD, PTSD phobias
GAS (escitalopram, paroxetine)
When are TCAs prescribed in anxiety?
2nd line for panic disorder, OCD
Mode of action of pregabalin?
Calcium channel blocker, increases GABA
What drug is best for somatic symptoms (palpitation, tremor) of anxiety?
Propanolol
Management of GAD?
CBT
SSRI
SNRI
Pregabalin
How long should treatment be continued in GAD?
Up to 12 weeks to assess efficacy
Contie for 18 months
When stopping, reduce dose over 4 weeks to avoid discontinuation syndrome
What drugs should be AVOIDED in panic disorder?
BZD
Propranolol
Buspirone
Bupropion
How long should treatment be continued in panic disorder?
6 months
Management of OCD
CBT & ERP
SSRI
SSRI plus CBT ERP
Clomipramine (TCA)
How long should the SSRI be continued if effective in OCD management?
1 year
Management of mild PTSD?
Watchful waiting
Management of PTSD more than 3 months after trauma?
Trauma focused CBT or EMDR
Are drugs commonly given in PTSD?
No; if so use paroxetine or mirtazapine
