Anxiolytics Flashcards
Define anxiolysis and sedation
Anxiolysis: a level of sedation in which a person is very relaxed but still conscious and able to answer questions and follow instructions
Sedation: depression of awareness, patient’s response to external stimuli becomes limited
What are the pharmacodynamics of benzodiazepines and z-drugs?
Benzodiazepines:
- act on GABA receptors
- allosteric agonists which increase the frequency of opening of the channel pore (Cl-)
Z-drugs (zopiclone, zaleplon, zolpidem):
* act on same receptors but are structurally different to benzodiazepines
What are the pharmacokinetics of benzodiazepines and z-drugs?
Benzodiazepine:
- well absorbed orally (peaks quickly 30mins-2hrs)
- highly lipophilic (absorbed fast and rapidly enters CNS)
- highly protein bound (big reservoir leads to longer acting)
- hepatic metabolism - produces active metabolites
What are the classes of drugs used to manage anxiety?
- anti-depressants
- benzodiazepines
- z-drugs
- B-blockers
- melatonin
- sedating anti-histamine
Define tolerance, dependence and withdrawal and its relation to benzodiazepines
Tolerance: physiological reaction characterised by a decrease in the effects of a drug with chronic administration
- develops quickly in benzodiazepines for sedative effects and slowly for anxiolytic and anticonvulsant effects
- neuroadaptive: desensitisation of GABA and sensitisation of NMDA
Dependence: when drug taking becomes compulsive psychologically and physically
Withdrawal: result of physical dependence - increased anxiety/depression, disturbed sleep, pain, stiffness, muscular aches, convulsions (can occur within 4 weeks)
What are the clinical indications for prescription of anxiolytics?
- management of acute alcohol withdrawal
- terminal care pathway
- to enable potentially uncomfortable diagnostic and therapeutic procedures to be carried out
What is the role of B-blockers in managing anxiety?
- reduces HR in anxiety
* contraindicated in asthma
Describe the therapeutic role of melatonin
- clinically used in children with sleep disturbance/insomnia
- naturally occurring hormone in the pineal gland
What is some advice to improve sleep hygeine?
- establish regular pattern of going to bed and getting up
- regular exercise preferably in the morning and not within 4hrs of going to bed
- no caffeine/alcohol/smoking within 6 hrs of going to bed
- no screen time 30mins before bed
- avoid naps during the day
- keep bed for just sleep and sex
What are the 5 major effects of benzodiazepines?
- anxiolytic: reduces anxiety (alpha 2 and 3 receptors)
- hypnotic: induces sleep (alpha 1 receptors)
- reduces muscle tone
- anterograde amnesia
- anticonvulsant effect
What can be given to counteract benzodiazepines and its side effects?
- flumazenil in 100 mcg increments (competitive benzodiazepine antagonist)
- can cause agitation and convulsions
- nausea and vomiting
In benzos overdose supportive management preferred
What are the concerns associated with benzodiazepine use?
- increased risk of hip fractures
- risk of worsening dementia symptoms when drug is reduced or tapered off
- sedating effect which can cause accidents as awareness and alertness is affected
What are the clinical signs suggestive of chronic alcohol consumption?
- raised MCV
- pancytopenia (result of bone marrow suppression)
- folate deficiency
- prolonged prothrombin time
What are the clinical indications for benzodiazepines?
- last days/weeks of life
- managing anxiety
- massive terminal haemorhage
- agitated delirium
- breathlessness/respiratory distress
Midazolam drug of choice
Describe the use of benzodiazepines for prolonged seizures
After exclusion of hypoglycaemia
- give O2
- IV lorazepam
