IV Sedatives Flashcards
Barbiturates increase the _____ of the opening of the chloride channel
duration
Thiobarbiturates have a ____ molecule in the 2nd position which increases lipid solubility and ____.
sulfur, potency
Oxybarbiturates have a ____ molecule in the 2nd position
oxygen
Adding a phenyl group at the 5th carbon increases the ______. Which med is this?
Anticonvulsant effect. Phenobarbital
What is Thiopental mechanism of action?
GABA-A agonist Depresses reticular activating system in the brainstem.
What is the following for Thiopental: Dose: Onset: Duration: Clearance: Side effects:
Dose: 2.5-5mg Onset: 30-60 sec Duration: 5-10 min Clearance: Liver P450 enzyme S/E: hypotension, histamine release, respiratory depression, bronchoconstriction, decrease in cerebral blood flow and metabolic demand. No analgesia
What is the most common and dangerous type of porphyria
Acute Intermittent Porphyia
What causes porphyria?
Defect in heme synthesis that promotes the accumulation of heme precursors
What things make acute intermittent porphyria worse?
ALA synthase, emotional stress, prolonged NPO status, CYP450 induction
What are signs and symptoms of porphyria?
Severe abdominal pain, N/V, anxiety, muscle weakness, seizures, coma
What are drugs to avoid with porphyria?
Barbs Etomidate Ketamine Ketorolac Amio Many Ca Channel Blockers Birth Control pills
What types of anesthetic management is done for porphyria?
hydration! Glucose Heme arginate Prevent Hypothermia consider regional
What are the following for Propofol?
MOA: Dose: Onset: Duration: Clearance:
MOA: GABA-A agonist Dose: 1-2mg/kg Onset: 30-60sec Duration: 5-10 min Clearance: liver P450
What are side effects of Propofol:
Cardiac: Decreased BP, SVR, preload, contractility
Respiratory: less sensitive to increasing CO2, decreased TV
CNS: decreased CMRO2, ICP, IOP
green/cloudy urine
The clearance of Propofol exceeds what the liver is able to handle, how else is it excreted?
the lungs
About how long does it take to have peak brain concentration with Propofol?
1 min
What are risk factors for Propofol Infusion Syndrome (PIS)
Propofol dose >4mcg/kg/hr (67mcg/kg/min) Infusion >48hr Sepsis Continuous catecholamine infusions high-dose sterioids significant cerebral injury
What are s/s of propofol infusion syndrome?
acute, refractory bradycardia that leads to asystole plus one of the following: metabolic acidosis rhabdo enlarged fatty liver renal failure HLD lipemia**early clinical sign
What is the treatment for propofol infusion syndrome?
stop propofol maximize gas exchange cardiac pacing Glucagon ECMO CRRT Phosphodiesterase inhibitors
What is Methohexital used for?
ECT
Phenobarbital is excreted through the ___ which is different than other barbiturates, which are metabolized by______
urine, P450 enzymes
What is the following for Propofol:
MOA: Dose: Onset: Duration: Clearance:
MOA: GABA-A agonist Dose: 1-2mg/kg Onset: 30-60 sec Duration: 5-10 min Clearance: P450 and lungs
What are risk factors for propofol infusion syndrome (PIS)?
High propofol dosing (>4mcg/kg/hr or 67mcg/kg/min) Duration >48hr Sepsis Continuous catecholamine infusions High dose sterioids Significant cerebral injury
What are side effects of propofol infusion syndrome?
Acute refractory bradycardia that leads to asystole + one of the following:
Metabolic acidosis Rhabdo Enlarged fatty liver Renal failure HLD lipemia (early sign)
What is the treatment for propofol infusion syndrome?
stop propofol maximize gas exchange cardiac pacing Glucagon ECMO CRRT Phosphodiesterase inhibitors
What is the following for Etomidate:
MOA: Dose: Onset: Duration: Clearance:
MOA: GABA-A agonist Dose: 0.2-0.4mg/kg Onset: 30-60 sec Duration: 5-15 min Clearance: P450 and plasma esterases
What are the benefits of Etomidate?
More cardiac stability than propofol, less respiratory depression, short half life
When should you use caution with Etomidate?
It decreases adrenocortical function for 5-8 hr so use with causes in pts with sepsis or acute adrenal failure. increased mortality rate. Also avoid if patient has had acute intermittent porphyria
What do benzos do to let Chloride in?
The frequency of the channel opening increases
What is the following for Midazolam:
MOA: Dose: Onset: Duration: Clearance: Metabolite:
MOA: GABA-A agonist, increased frequency of channel opening
Dose: 0.1 mg/kg
Onset: 30-60 sec
Duration: 20-60 min
Clearance: Liver & intestines P450 enzymes
Metabolite: 1-hydroxymidazolam (half potency, renal failure prolongs effect)
Respiratory effects of midazolam:
induction dose causes respiratory depression. Opioids potentiate effect.
CNS effects of midazolam:
Anticonvulsant
Antianxiety
amnesia
antispasmodic
Uses for diazepam:
anticonvulsant, antispasmodic, prevent emergence delirium after ketamine
How long does it take for Lorazepam to reach peak effect?
20-30 min (slow onset)
How long does Lorazepam work?
6-10 hrs
What is a short acting benzo that is used for helping fall asleep?
Triazolam
What is the reversal for benzos and what is the MOA?
Flumazenil, GABA-A antagonist
What is the dosing for Flumazenil?
0.2mg IV, titrated to 0.1mg Q1min.
What is the following for Ketamine:
MOA: Dose: Onset: Duration: Clearance: Metabolite:
MOA: NMDA antagonist Dose: Induction: 1-2mg/kg, Maint: 1-3mg/kg Onset: 30-60 sec Duration: 10-20 min Clearance: Liver P450 Metabolite: Norketamine
Does ketamine decrease the respiratory drive?
No!
What are cardiac effects of Ketamine?
increased: SNS tone Cardiac output HR SVR PVR
myocardial depressant
What are respiratory effects of Ketamine?
Bronchodilation
Maintains respiratory drive
Increased oral and pulmonary secretions (may give glyco to avoid)
What are CNS effects of Ketamine?
Increased: CMRO2 blood flow ICP IOP EEG activity Nystagmus Emergence Delirium
What are some other uses and effects of Ketamine?
Treatment of depression, chronic use can cause ulcerative colitis, avoid with pts with porphyria, lowest amount of protein binding, relieves somatic pain >visceral pain, good for frequent dressing changes and pre-existing chronic pain syndromes
What is the following for Dexmedetomidine?
MOA: Dose: Onset: Duration: Clearance:
MOA: Alpha-2 agonist, decreased norepi released and inhibits locus coeruleus in the Pons
Dose: bolus: 1mcg/kg over 10 min, maint: 0.4-0.7 mcg/kg/hr
Onset: 10-20 min
Duration: 10-30 min after infusion
Clearance: liver P450 enzymes
What are cardiac effects of Dex?
bradycardia and hypotension. Can get hypertension right after bolus dose
What are respiratory effects of Dex?
None
What are CNS effects of Dex?
decreased blood flow, easily aroused, no amnesia
What are some other effects of Dex?
impairs thermoregulatory response (should shiver but dont)
decreased emergence delirium in children
analgesia d/t decreased substance P and glutamate release in dorsal horn
Useful for wake up tests
What is the reversal for Scopolamine?
Physostigmine
