L15 - barbiturates and benzodiazepines

sedative hypnotics

drugs that depress the CNS

what is a barbiturate

sedative-hypnotic drug that depresses the CNS

what are barbiturates used for medically

sedation

sleep

anticonvulsant effects

anaesthesia

alcohol withdrawal

anxiety

why barbiturates no longer wildly used for insomnia or anxiety

they have rapid tolerance

severe withdrawal effects

low safety margin

what is a benzodiazepine

a sedative/anxiolytic drug

used for anxiety, agitation, insomnia, seizures, alcohol withdrawal

why are benzodiazepines safer than barbiturates

less tolerance

less withdrawal side effects

higher therapeutic index

lethal overdose is harder to take

GABA A receptor

ionotropic receptor that forms a chloride channel

gaba increases chloride entry

increases hyperpolarisation and inhibition

how does benzodiazepines and barbiturates affect GABA A receptors

they enhance GABA induced chloride inlfux

what is the key difference between benzodiazepine and barbiturates at the GABA A channel

barbiturates make the chloride channel stay open for longer

benzodiazepines make the chloride channel open more frequently

GHB

sedative-hypnotic structure similar to GABA

acts mainly through GABA B receptors and causes relaxation and social disinhibition

which GABA A receptors subunits are linked to different benzodiazepine effect

a1-containing receptors

• sedative and amnesic effects

a2-containing receptors

• anxiolytic effects