Benzo/Barbiturate/Flumazanil Flashcards
Benzo receptor
Ionotropic GABAa receptor
Benzo MOA
increase frequency of CL channel -> cell hyperpolarization -> depression of reticular activating system (RAS)
Benzo indication
anxiolytics, amnesia, emergence delirium, skeletal muscle relaxation (high dose)
Benzo Contraindication
Judicious use with other cardiorespiratory depressants
Benzo absorption
5-60 min for PO
Benzo Distribution
rapid penetration of CNS (7 min for IV midazolam)
Benzo Biotransformation
Hepatic CYP450, phase 2 glucuronidation
Benzo Elimination
Renal half-time: 2.5 hr (midazolam)
Benzo Neuro Effect
Down CMRO2, CBF, ICP anticonvulsant anxiolytics,sedation antegrade and retrograde amnesia disinhibition, dysphoria Risk post cognitive dysfunction
Dysphoria is most commonly seen in what population?
PTSD (military, sexual assault)
Benzo resp/cardiac effects
decrease RR,Vt, MV, protective reflexes, hypoxic and hypercarbic ventilatory response
minimal card effect
Midazolam dose
premed: 2-4 mg IV
elderly: 0.5-2 mg IV
ped: 0.5 mg/kg PO (max 40 mg)
seizure termination: 2-5 mg IV (max 10 mg)
Midazolam onset
IV: 2-3 min
PO: 15-20 min
Midazolam peak
7-10 min
Midazolam Duration
30-60 min
Flumazenil MOA
lower frequency of Cl channel opening -> cell repolarization
Flumazenil distribution
peak 5 min
Flumazenil biotransformation
hepatic phase 2
Flumazenil elimination
renal half time 0.5-1 hr
Flumazenil neuro effects
increase CMRO2, CBF, ICP, proconvulsant properties, agitation, confusion, delirium, hallucinations
Flumazenil resp/card effects
increase RR, Vt, MV, protective reflexes, hypo and hypercarbic ventilatory responses
htn and dysrhythmia with rapid admin
Flumazenil dose
0.2 - 0.5 mg IV for benzo reversal, max dose 1 mg
benzo contraindication
pregnant woman
