Induction Drugs Flashcards
Midazolam
Available 1-5mg/mL
Use 3mL syringe
Dose 0.02-0.04mg/kg IV
Fentanyl
Available 50mcg/mL
Use 5mL syringe
Dose 1-3mcg/kg
High-dose as sole anesthetic 50-150mcg/kg (cardiac surgery induction)
Lidocaine 2%
Available 20mg/mL
Use 5mL syringe
Dose 1-1.5mg/kg IBW
Propofol
Available 10mg/mL
Use 20mL syringe
Dose 1.5-2.5mg/kg
Etomidate
Available 2mg/mL
Dose 0.2-0.4mg/kg
Ketamine
Available 5-100mg/mL
Dilute to 10mg/mL
Dose 1-2.5mg/kg
Succinylcholine
Available 20mg/mL
Use 10mL syringe
Dose 0.5-1.5mg/kg
RSI 1.5mg/kg
*Based on ACTUAL body weight
Rocuronium
Available 10mg/mL
Use 3mL syringe
Dose 0.6 OR 1.2mg/kg (RSI)
*Based on IBW
Vecuronium
Available 1-2mg/mL
Use 5-10mL syringe
Dose 0.08-0.1mg/kg
*Based on IBW
Cisatracurium
Available 2mg/mL
Dose 0.15-0.2mg/kg
*Based on IBW
Midazolam PK/PD
GABA allosteric Phase 1 oxidation via CYP450 Active metabolites x2 Elimination not altered by renal failure Exaggerated effects in liver dysfunction
Midazolam Onset
2min
Midazolam Duration
1-6hr
Midazolam SE
↓CBF & CMRO2 Not neuroprotective Antegrade amnesia Dose dependent respiratory depression Minimal cardiac effects Fetal depression Contraindicated in pregnancy
Fentanyl PK/PD
Phenylpiperidine
Opioid agonist
Pulmonary 1st pass effect → 2° peaks
Phase 1 oxidation
Fentanyl Onset
2-5min
Fentanyl Duration
0.5-1hr
Fentanyl SE
Allergy extremely rare Ø cross-reactivity Elderly exaggerated response d/t ↓clearance Similar side effects to Morphine NO histamine release Bradycardia Minimal ↑ICP Seizure activity & myoclonus
Lidocaine PK/PD
Local anesthetic
Weak base amide
Preferentially binds to open & inactive VGNa+ channels
Blocks K+ channels, Ca2+ channels, & GPCRs to lesser extent
Pulmonary 1st pass effect
Hepatic metabolism via CYP450
Lidocaine Onset
45-90sec
Lidocaine Duration
10-20min
Lidocaine SE
Blunts SNS response to intubation
Improves bowel function return in laparoscopic cases
Accumulation & toxicity concern (infusion)
ERAS protocol
Propofol PK/PD
Sedative hypnotic GABA allosteric Hyperpolarizes cell via Cl¯ channels Weak acid Oxidation via CYP450 Active metabolite (insignificant) Pulmonary 1st pass effect
Propofol Onset
<40sec
Propofol Duration
5-10min
Propofol SE
Neuro protectant ↓CBF, ICP, CPP, CMRO2 Myoclonus Bronchodilation Respiratory depression Hypotension PRIS No analgesic properties Caution in cardiac compromised patients Lecithin or sulfate allergy (asthmatics) Decrease dose in elderly
Etomidate PK/PD
Sedative hypnotic GABA allosteric α2B adrenergic receptors Imidazole ring Single isomer R 5x more potent 75% albumin bound Rapid distribution Metabolism plasma esterases via hydrolysis & hepatic CYP enzymes
Etomidate Onset
30-60sec
Etomidate Duration
3-10min
Etomidate SE
↓CBF & CMRO2
↓ICP maintain CPP
Myoclonus
↓TV ↑RR
Ideal induction agent w/ unstable cardiac patient
Maintain BP
No analgesic properties
↑PONV incidence
Adrenocortical suppression (inhibits 11β-hydroxylase)
Contraindicated in porphyrias & critically ill septic shock
Ketamine PK/PD
Sedative hypnotic N-methyl-D-aspartate antagonist Disassociation between thalamocortical & limbic systems Weak GABAa action Racemic mixture Oxidation via CYP450 Dependent on hepatic blood flow Norketamine active metabolite
Ketamine Onset
30sec
Ketamine Duration
5-15min
Return to consciousness 10-20min
Full orientation 60-90min
Ketamine SE
Dissociative anesthesia Airway reflexes intact ↑secretions Potent amnestic/analgesic ↑ CBF, ICP, CMRO2 Nystagmus ↑IOP Maintain spontaneous respirations Bronchodilation SNS activation ↑HR ↑SVR Contraindicated in ophthalmic procedures
Succinylcholine PK/PD
Depolarizing NMB (agonist-antagonist)
Binds to nAChR & prevents ACh binding
ACh molecules linked via acetate methyl groups
Rapid hydrolysis via butyrylcholinesterase PChE
NO fade
Only Phase I
Dibucaine # >70 Heterogenous atypical 40-60
Homogenous <30
Elderly slower onset d/t ↓circulation & ↓PChE levels
Succinylcholine Contraindications
- Burn patients
- Abdominal infection
- Metabolic acidosis
- Closed head injury
- nAChR upregulation
- Myoglobinuria
- Pediatric patients <5yo
Succinylcholine Onset
30-60sec
Succinylcholine Duration
5-15min
Succinylcholine SE
Bradycardia or tachycardia Hyperkalemia 0.5mEq/dL Ventricular dysrhythmias ↑ICP & IOP ↑abdominal pressure Myalgias *Malignant hyperthermia
Rocuronium PK/PD
Steroidal Non-depolarizing neuromuscular blocker nAChR antagonist Competitively antagonizes ACh to block depolarization Hepatic & renal excretion Most commonly used & inconsistent
Rocuronium Onset
2-3min
RSI 1min
Rocuronium Duration
30-60min
Intermediate
Rocuronium SE
Allergic reactions
Histamine release
Vecuronium PK/PD
Steroidal Non-depolarizing neuromuscular blocker nAChR antagonist Pancuronium w/o quaternized methyl group ↓potency 1° hepatic metabolism Renal unchanged Elim 50-60% hepatic & 40-50% renal 3-OH metabolite
Vecuronium Onset
2-3min
Peak 5-7min
Vecuronium Duration
30-60min
Intermediate
Vecuronium SE
AVOID in renal impaired patients
Cisatracurium PK/PD
Benzylisoquinolinium
Non-depolarizing neuromuscular blocker
nAChR antagonist
Hoffman elimination - spontaneous degradation
Cisatracurium Onset
2-4min
Cisatracurium Duration
30-60min
Intermediate
Cisatracurium SE
NO histamine release
Atracurium cis-isomer
DOC hepatic & renal failure
