Sedatives/Induction Agents Flashcards
Barbs MOA
- Binds to GABAa (A/B)
- Glu inhibition @ AMPA
Barbs Pharmacokinetics
- Absorption: IV/ Barbies in the butt for kids
- *displays context sensitivity (infusion dose depends on elimination bc peripheral tissue is saturated)
- Metabolism by CYP
Barbs Pharmacodynamics
CV: ↓BP; tachycardia
Resp: ↓RR Cerebral: constricts cerebral vasculature
↓CBF ↓ICP, ↓oxygen consumption
Histamine release (ex. methohexital)
Barbs Interactions/Contraindications
- Contraindications: acute intermittent porphyria
- Avoid in hypovolemic pts, beta blocker therapy, CHF , asthma pts
- Consider dose reduction: interactions w/ opioid, alpha 2 adrenergic agonist, benzos, acute ethanol
Benzos MOA
- increased GABA affinity by binding to GABAa @ alpha 1 and gamma 2
Benzos Pharmacokinetics
A: IV/IM/PO D:Lipid solubility: M>D>L Half Life: D>L>M Duration: L/D>M -D: large Vd -L: large affinity to receptor M: D and M have active metabolites --D: desmethyldiazepam --> Oxazepam --> CONJUGATION --> Urine excretion --M: alpha hydroxymidazolam -->CONJUGATION --> Urine excretion
Benzos Pharmacodynamics
CV: some ↓BP, minimal HR (some increase with midazolam) Resp: some ↓RR Thrombophlebitis: D>M>>L Cerebral: ↓CBF ↓ICP, ↓oxygen consumption *anterograde amnesia*
Benzos Interactions/Contraindications
- Drugs that induce or inhibit metabolizing CYP P450
- Opioids + BZ = decrease in SVR (hypotension)
- Allow decreased MAC
- Additive sedative and RR depressants
Ketamine MOA
- *inhibit NMDA
* nACh
Ketamine Pharmacokinetics
A: IV/IM
D: lipophilic w/ rapid brain uptake
M: hepatic extraction
Ketamine Pharmacodynamics
*CV: increases BP, HR, CO, CBF, ICP Resp: ↓RR *analgesia *Hallucinations *inhibits NE reuptake
Ketamine Interactions/Contraindications
Alpha and Beta adrenergic antagonists block the symp response wanted by Ketamine.
Avoid in pts that have catecholamine depletion.
Additive effect: inhaled anesthetics, Propofol, BZ, GABA agents
Contraindications: CAD, HTN
Etomidate MOA
Binds to GABAa receptor and increases receptor affinity for GABA
Etomidate Pharmacokinetics
A: IV only
D: High protein binding/high lipid solubility (rapid onset)
M: by plasma esterases/hepatic CYP enzymes
Etomidate Pharmacodynamics
*CV: minimal to no CV depression
Cerebral perfusion well maintained
Preferred use in pts w/ high risk CV problems
- -LV impairment
- -cardiac tamponade
- -hypovolemia
Respiratory drive maintained unless combined w/ opioids.
Endocrine: Adrenal suppression (inhibits 11-beta hydroxylase)