Pharmacology of Anxiolytic Drugs Flashcards
(37 cards)
what drugs are used to treat anxiety
benzodiazepines antidepressants busiprone pregabalin beta-blockers (propanolol)
when is anxiety a disorder
when it affects concentration, fatigue, sleep and arousal
what is anxiety commonly co morbid with
substance abuse, BPAD, pain and sleep disorders, other anxiety disorders
what are the core symptoms of anxiety and what part of the brain is responsible for them
fear: panic and phobia = amygdala centered circuit
worry: anxiety, apprehension, obsessions = cortico- striatal- thalamic- cortical circuit
what does the amygdala do
intergrates sensory and cognitive information
what part of brain: affect of fear
anterior cingulate cortex/ orbitofrontal cortex
what part of brain: avoidance
periaqueductal gray (fight/ flight)
what part of brain: endocrine element of fear
hypothalamus (increases cortisol)
what part of brain: autonomic output during fear
locus coeuleus (increase BP and HR)
what part of brain: re-experiencing of fear
hippocampus (traumatic memories)
what neurotransmitters are involves in amygdala centred circuits
5HT (Serotonin) GABA (gamm-aminobutyric acid) glutamate CRF (corticotophin releasing hormone) NE (norepinephrine) voltage gated ion channels
what is GABA
main inhibitory neurotransmitter
what does GABA do
reduced the activity of neurones in amygdala and CSTC (cortico-striato-thalamo-cortico) circuit
what do benzodiazepines do
enhance GABA action (inhibit neurones in maygdala and CSTC circuit)
what are the main GABA receptors
GABA-A
GABA-B
GABA-C
what else activates GABA-A
benzodiazepines, barbiturates, general anaesthetics: alcohol, steroids, propofol, haloethane
explain the action of benzodiazepines
binds at allosteric site on GABA receptor
this increases effect of GABA on channel and increases the activity of the GABA recpetor
=increases amount of Cl- passing into neurone
this hyperpolarises membrane potential making it less likely for the neurone to produce an AP
give examples of benzodiazepines
lorazepam midazolam diazepam (valium) alprazolam (xanax) chlordiazepoxide
all end in epam (-chlordiazepoxide)
what are the pharmacological effects of benzodiazepines
reduce anxiety and aggression hypnosis/ sedation muscle relaxant anticonvulsant effect anterograde amnesia
what are the clinical uses of benzodiazepines
acute treatment of extreme anxiety hypnosis alcohol withdrawal mania delirium rapid tranquilisation premedication before surgery or during minor procedure status epilepticus
what are potential problems with benzodiazepines
fairly safe in overdose (antagonist flumazenil)
paradoxical aggression
anterograde amnesia & impaired coordination
tolerance + dependence
what are the symptoms of benzodiazepine withdrawal
abdo cramps increased anxiety, panic attacks physical symptoms (muscle tension, chest pain, palpitations, sweating, shaking) blurred vision insomnia dizziness headaches inability to concentrate nausea and vomiting tingling in hands and feet restlessness sensory sensitivity
what causes benzodiazepine withdrawal symptoms
rapid withdrawal - confusion, psychosis, convulsions, tachycardia, sweating, hypertension, agitation, tremor
neuroadaption of the GABA response: chronic treatment- anxiety/ convulsions
how do you withdraw patient from benzodiazepines
transfer to equivalent dose of diazepam/ chlordiazepoxide- preferably taken at night
reduce tose every 2-3 weeks in 2-2.5mg steps (maintain dose is symptoms occur)
reduce dose further (if necessary in smaller steps)
stop completely (can take 4 weeks- year+)
