2.3 more on benzos Flashcards
high dose and long use
develop tolerance and dependance,
produce pharmacodynamic (tissue) tolerance;
no pharmakokinetic tolerace like barbiturates;
can also produce cross tolerace
tolerance develops towards
hypnotic and anticonvulsant actions —NOT anxiolytic actions
lorazepam does not have
active metabolites_.goes straight to conjugation
abrupt wothdrawal leads to
withdrawal symptoms/syndrome
withdrawal symptoms
confusion, anxiety, tremor and convulsion (seizures), agitation and restlessness, insomnia
withdrawl syndrome
generally slower in onset and less intense for benzos than barbitruates, bc of long half life of most of the bzds
triazolam
short acting bzd that cause
more abrupt and severe withdrawal effects
Precautions of BZDs
elderly,
liver disease,
potentiate the effects of alcohol and other CNS depressants
Therapeutic usese of benzos
anxiety disorders, sleep disorders, seizures, muscular disorders, alcohol withdrawal
benzos and anxiety
should not be used to alleviate the normal stress of everyday life,
should be reserved for continued severe anxiety and,
should be used only ofr short period of time,
longer acting agents (diazepam) should be used,
not tolerance to anti-anxiety effects
benzo in sleep disorders
bzds can be used to reduce sleep incuction time,
to reduce number of awakenings,
to increase duration of sleep,
No hangover effect and person awakes fresh the next morning
benzos for sleep disorders
tem azepam,
ox azepam,
tri azolam
benzos for seizures
benzos having longer half-lives and those which could cross brain rapidly can be used
benzos for seizures
clon azepam
di azepam,
lor azepam,
nitr azepam
benzo in muscular disorders (central skeletal muscle relaxant)
skeletal muscle spasm, eg in musle strain;
in spasticity from degenerative disorders,
eg MS and cerebral palsy
benzo in pre-anesthetic medication
di azepam
lor azepam,
mid azolam
benzo for alcohol withdrawl
long-acting bzds are used
benzo for alcohol withdrawl
Chlor diazepoxide,
Diazepam
lorazepam and oxazepam used for
pts with liver disease
Flumazenil
competitive antagonist at BZD receptors – antidote for bzd overdoes (can not reverse the CNS depression caused by barbiturates and alcohols), also used to reverse the sedative action of bzds during anesthesia
flumaznil administration
not given orally as it has high first pass metabolism in liver
(half life 1 hr),
only available for IV use,
percipitates withdrawal symptoms in bzd dependent pateints
