meds; benzos Flashcards
Diazepam dose IV and PO
Valium; IV 0.1 mg/kg
PO; 0.2 mg/kg
Lorazepam dose
Ativan; 0.04 mg/kg
Diazepam onset
1-5 min
Diazepam duration
2-6 hr
Lorazepam onset
1-5 min
lorazepam duration
6-10 hr
Midazolam dose bolus and gtt
Versed; 1-5 mg (0.05mg/kg)
gtt; 1-7 mg/hr
Midazolam onset
1-5 min
Midazolam induction dose
0.1-0.2 mg/kg
Midazolam duration
15-80 min
midazolam maintenance dose
precede induction dose with fentanyl 50-100 mcg
Flumazenil dose, repeat and MAX
0.2 mg (repeat 0.1 q 1 min to a total of 1mg in the first hour and MAX 3 mg)
Midazolam peak
5 min
flumazenil concetration
0.1 mg/ml vials.
Flumazenil onset
1-5 min
Flumazenil duration
30 min
other name for flumazenil
Romazicon
MOA of midazolam
increase gaba affinity to GABA A receptor -> increase Cl- opening -> hyperpolarized post synaptic membrane = inhibition of depolarization
spinal cord mediated skm relaxation but not paralysis
Midazolam metabolism
Cyp3A4
acitve metabolites 1/2 as active (1-hydroxymidazolam)
Midazolam side effects
inhibits plat aggregation?
decreased T - cell and immune response (gtts mostly)
teratogenic
Midazolam in the elderly
half life doubles due to decreased hepatic flow
pulmonary effects of midazolam
decreased hypoxic drive and decreased swallow and cough reflex
> depression with COPD
Diazepam metabolism
CPY 3A
active metabolites (48-96 hrs)
as potent as parent
Diazepam Side effects
-return to drowsiness in 6-8 hrs
-can produce isoelectric EEG
-Pain on injection
Lorazepam metabolism
Conjugation to inactive metabolites
diazepam MOA
binds to gaba /alpha/ gamma subunits
Gaba -> cl channels opening hyperpolarize cell membrane -> no ap transmitted
alpha 1; sedation, amnetic, anticonvulsant
found in cerebral cortex and thalamus
alpha 2; anxiolytic, skm
found in hypocampus and amygdala
Flumazenil MOA
Competitive antagonist -> increase affinity to benzodiazepine receptor
Side effects of flumazenil
anxiety, htn, tachycardia, changes MAC of volatiles
Who do we not give flumazenil to?
Sz pts
Benzos are usually weak acids or bases?
Acids
Benzo potency
Lorazepam > Midazolam > Diazepam.
Lorazepam ~ 5 times more potent than Midazolam.
Midazolam ~ 5 times more potent that Diazepam
