Oral: Induction Agents Flashcards
Propofol: Drug Class
Non-Barbituate Induction agent / Sedative / Hypnotic
Propofol: MOA
1: discourages dissociation of GABA from GABA-A receptor; increasing Cl- conduction, hyperpolarized cell, and decreases neuronal transmission.
2: Also inhibits glutamate at the NMDA receptor.
Propofol: Pharmacokinetics
90% PB; highly lipid soluble
onset- rapid 30sec;
DOA- short < 15min (terminated by rapid redistribution);
E1/2- 1 hrs;
conjugated in liver by CYP450 & excreted in the urine;
extrahepatic metabolism;
active metabolite: 4-hydroxy-propofol (1/3 pot);
Propofol: Side Effects
⬇ CBF, CMRO2, ICP; isoelectric EEG; severe drop in BP and SVR, dose dep ⬇RR, bronchodilation, pain on injection
Propofol: Contraindications
Soy, egg allergy; hypovolemia, use with caution in elderly or those w/ myocardial depression.
Propofol: Dosing
Induction 1-2.5 mg/kg IV (reduce w/ increasing age &/or myocardial depression);
Sedation 25-100 mcg/kg/min;
maintenance 100-300 mcg/kg/min;
antiemetic 10-20 mg IV
Ketamine: Drug Class
Non-Barbituate Induction agent / Sedative / Hypnotic
Ketamine: MOA
Blocks NMDA receptor (decreases ion influx, decreases neurotransmission),
opioid receptor agonist (analgesia),
muscarinic antagonist
Ketamine: Pharmacokinetics
12% (poor) PB; highly lipid soluble; onset- rapid 30sec; DOA= short < 15min; E1/2- 2-3 hrs; metabolized by CYP450 to norketamine, then hydrolized and conjugated to be water soluble and excreted in urine. Some eliminated unchanged in urine and feces.
norketamine (active metabolite)~30%
Ketamine: Side Effects
⬆CBF, CMRO2, ICP & IOP, emergence delerium, ⬆SNS response b/c it inhibits NE uptake; direct myocardial depressant, ⬆ HR, SVR, BP; bronchodilation; ⬆ saliva, hallucinations, myoclonus, potentiates NMB; causes dissociative anesthesia.
Ketamine: Contraindications
Psych disorders, head injury, eye injury or surgery, CAD, HTN/PHTN, pheochromocytoma
Ketamine: Dosing
Induction 0.5-2 mg/kg IV;
Sedation/Analgesia 0.2-0.5 mg/kg;
maintenance 1-2 mg/kg/hr IV, 5-10 mg/kg IM/PR?
Etomidate: Drug Class
Non-Barbituate Induction agent / Sedative / Hypnotic
Etomidate: MOA
Mimics GABA at GABA-A receptors and increases affinity for GABA to GABA-A receptor. Increases Cl- conduction, hyperpolarizes cell, and decreases neuronal transmission.
Etomidate: Pharmacokinetics
75% PB; lipid soluble; onset- rapid 30-60sec; DOA- short < 15 min; E1/2= 3 hrs; liver hydrolysis by CYP450 and metabolized by plasma esterases and excreted in urine and bile.
Etomidate: Side Effects
decrease CBF, CMRO2, ICP, can increase EEG- causing seizures; NO change in BP, HR, SVR, CO- very cardiac stable; Potentiates NMB; 30-40% N/V; myoclonus; hiccups; adrenocorticoid suppression - may need cortisol replacement; pain on injection
Etomidate: Contraindications
seizures, porphyria, Addison’s disease/adrenal insufficiency
Etomidate: Dosing
induction- 0.2-0.6 mg/kg;
sedation- 5-8 mcg/kg/min;
maintenance- 10 mcg/kg/min
Dexmedetomidine (Precedex): Drug Class
Non-Barbituate Induction agent / Sedative / Hypnotic
Dexmedetomidine (Precedex): MOA
Alpha 2 agonist;
⬇ NT release (presynaptically) causing sedation, anxiolysis, analgesia;
Dexmedetomidine (Precedex): Pharmacokinetics
90% PB; water soluble; Onset- Rapid < 5 min DOA- < 2hr E1/2- 3 hrs; conjugated in liver by CYP450, excreted in urine and bile;
Dexmedetomidine (Precedex): Side Effects
⬇ CBF but no change in CMRO2 & ICP; ⬇ BP, HR, SVR; minimal change to RR and small ⬇ in TV; potentiates the effects of opioids and anesthetics; ⬇thermoregulation;
Dexmedetomidine (Precedex): Contraindications
Afib, HB, severe bradycardia, pts that cannot tolerate lower BP or HR
Dexmedetomidine (Precedex): Dosing
1 mcg/kg over 15 min bolus, then 0.2- 1 mcg/kg/hr
