Hypnotics and Anxiolytics Flashcards
What are the indications for benzodiazepines?
Short term (2-4wks only) relief of severe/disabling/unacceptably distressing anxiety (anxiolytic) +/- insomnia (hypnotic/sedative) or short term psychosomatic/organic/psychotic illness
Not for mild anxiety
Only for severe insomnia
What is the mechanism of action for benzodiazepines?
Increase effects of inhibitory GABA by helping to hyperpolarise neurons and reducing the lieklyhood of neuronal firing, has a calming effect on many functions of the brain
Short (1-12) - midazolam intermediate (12-40) - lorazepam, nitrazepam, temazepam long acting (45-250hr half lives) - diazepam, chlordiazepoxide (alcohol withdrawal)
What are the common side effects of benzodiazepines?
Drowsiness (though often desired), dizziness, reduced concentration and coordination, decreased libido and erection problems, depression, respiratory depression, hypotension
Long term use can have a negative impact on cognition and mental health
How does benzodiazepine dependence and withdrawal work?
Sudden cessation should be avoided or confusion/toxic psychosis/convulsion/DTs may occur
Withdrawal syndome may appear any time up to 3wks (more common and shorter with shorter acting drugs) - insomnia, anxiety, loss of appetite/weight, tremor, perspiration, perceptual disturbances - some may continue for wks-months;
Short term use can taper within 2-4wks; longer users should reduce over months - reduction regimen should be done on diazepam so switch should be made
What are hypnotics used for?
Management of insomnia
Underlying cause should be found + treated
Short acting - with sleep onset insomnia, next day sedation undesirable or elderly
Long acting - poor sleep maintenance causing daytime effects, anxiolytic effeects needed in day or day sedation is acceptable
What hypnotics are available and indicated for?
Benzos
Zopiclone and zolpidem (Z-drugs) - act at benzo receptors, short half life
Antihistamines - promethazine (available to public), stops working after a few days
Melatonin - available for adults >55
What are the Z drugs?
Similar effects to benzodiazepines but are different structurally
They act on the α2-subunit of the GABA receptor - causing an enhancement of the actions of GABA to produce the therapeutic and adverse effects
They can be divided into 3 groups:
Imidazopyridines: e.g. zolpidem
Cyclopyrrolones: e.g. zopiclone
Pyrazolopyrimidines: e.g. zaleplon
What are some indications for Z drugs
.
What are some side effects and withdrawal effects of Z drugs?
Similar to benzodiazepines:
…
Agitation, bitter taste in mouth, constipation, decreased muscle tone, dizziness, dry mouth, increase the risk of falls in the elderly
Withdrawal:
Convulsions, tremors and hyperventilation
