Anxiety Disorders - Pharmacology Flashcards
Name 5 drugs/drug groups that can be used to treat anxiety?
Benzodiazepines, anti-depressants, buspirone, pregabalin, beta blockers
How long can benzodiazepines be used for in the treatment of anxiety?
Short term only, < 2 weeks
What beta blocker is the most likely to be used for anxiety?
Propranolol
What drug class is the mainstay of treatment for anxiety?
Anti-depressants
What are the two core features of anxiety?
Fear and worry
What are the two main anxiety disorders which are primarily characterised by fear?
Phobias and panic disorder
What are the two main anxiety disorders which are primarily characterised by worry?
GAD and OCD
The amygdala centred circuit is responsible for which core symptom of anxiety?
Fear
The cortico-striatal-thalamic-cortical circuit is responsible for which core symptom of anxiety?
Worry
What is GABA?
The main inhibitory neurotransmitter in the brain
What is the role of GABA?
To reduce the activity of neurones in the amygdala and CSTC tract
What is the role of a benzodiazepine?
To enhance the action of GABA (hence causing further inhibition)
Which GABA receptor is the target of benzodiazepines?
GABA-A
What are some examples of drugs which act on GABA-A receptors?
Benzodiazepines, barbiturates and alcohol
Where do benzodiazepines bind to GABA-A receptors?
At a site which is separate from the GABA binding site
Benzodiazepines binding to GABA-A receptors at a site different to GABA itself has what effect?
Positive allosteric effect
What happens when GABA/benzodiazepines bind to the GABA-A receptor?
An ion channel opens, allowing Cl- ions to pass through causing hyperpolarisation, making it less likely that a neurone will fire an action potential
Give some examples of benzodiazepines?
Lorazepam, diazepam, chlordiazepoxide
What are the pharmacological effects of benzodiazepines?
Reduce anxiety and aggression, muscle relaxant, anti-convulsant, hypnosis/sedation
The choice of benzodiazepine drug is usually made based on what?
Duration of action
Give some examples of uses of benzodiazepines?
Acute anxiety, delirium, mania, alcohol withdrawal, status epilepticus
Are benzodiazepines safe in overdose?
Yes, fairly
What is the antagonist which can be used in a benzodiazepine overdose?
Flumazenil
What are some downsides to the use of benzodiazepines?
Paradoxically can cause aggression, anterograde amnesia and impaired co-ordination as well as tolerance and dependence
Name some symptoms which may be seen in benzodiazepine withdrawal?
Increased anxiety and depression, abdominal cramps, insomnia, dizziness, blurred vision, headaches, N+V
Benzodiazepine withdrawal can present similarly to what?
Delirium tremens
What are the two main causes of benzodiazepine withdrawal?
Rapid withdrawal of the drug, neuroadaptation of GABA response
What are some symptoms which may occur if a benzodiazepine is stopped suddenly?
Hypertension/tachycardia, confusion, psychosis, convulsions, sweating, agitation, tremor
What causes neuroadaptation of the GABA response?
Chronic treatment with benzodiazepines decreases the response to GABA
If you are wanting to withdraw a patient from lorazepam, what is the first step?
Change them to the equivalent dose of diazepam or chlordiazepoxide, and take them at night
How should you reduce the dosage of benzodiazepines?
Reduce dose every 2-3 weeks, by 2-2.5mg
What should you do if withdrawal symptoms occur while taking a patient off benzodiazepines?
Maintain the dose that you are on until symptoms resolve
How long can it take to completely withdraw benzodiazepines?
4 weeks - 1 year
What are some factors which can speed up the withdrawal of benzodiazepines?
If the person is an inpatient or if they haven’t been on it for too long
What is the key neurotransmitter that innervates the amygdala?
Serotonin
Why are anti-depressants useful in anxiety?
Many symptoms overlap - acutely, they cause increased extracellular serotonin, and chronically they have anti-anxiolytic properties
SSRIs are useful in the treatment of which anxiety disorders?
GAD, panic disorders, OCD, PTSD, phobias
When are tricyclics used in the treatment of anxiety disorders?
2nd line in OCD and panic disorder
What SNRI is most likely to be used in anxiety? What anxiety disorder is this most likely to be used for?
Venlafaxine, GAD
What anxiety disorder may an MAOI be used for?
Social anxiety
What is pregabalin?
A Ca++ blocker, GABA enhancer
When is pregabalin used in anxiety?
If unresponsive to other treatments
When are beta blockers used in anxiety?
For somatic symptoms e.g. palpitations, tremor
