Pharmacology: Inhaled and IV anesthetics Flashcards
General Principle for Inhaled Anesthetics: Minimal Alveolar Concentration
MAC = concentration at which 50% of patients do respond to surgical incision
- Potency = 1/MAC
General Principle for Inhaled Anesthetics: MOA
Inhibition of CNS by increasing action of GABA receptor and decreasing 5Ht and Glutamate receptors
General Principle for Inhaled Anesthetics: Solubility and efficacy
DECREASE solubility = FASTER induction and recovery time! this is because the drug solubilizes and redistributes to other parts of the body instead of going more towards the brain.
Inhaled Anesthetics: Nitrous Oxide and Sevoflurane
- Solubility, System Effects, Adverse Effects
Solubility: Both have low solubility (NO is lower)
System Effects:
- Increase Cerebral Vasodilation and therefore blood flow
- Decrease cardiac contractility and Mean Arterial Pressure
- Bronchodilation
Adverse Effect: Malignant Hyperthermia, give Dantrolene as Tx.
Inhaled Anesthetics: special consideration for underlying airway problems
Sevoflurane/Halothane given. Not NO.
Barbiturates: Thiopental and Methohexital
- MOA
Increase DURATION of Cl- channel opening at GABAa receptor (largely replaced by Propofol (GABAa receptor potentiator))
Most frequent administered drug for induction (+ maintenance of anesthesia)
Propofol (GABAa Potentiator)
Esp. used in pts with compromised myocardial contractility in the induction of anesthesia
Etomidate = comparatively has a modest decrease in systemic BP (GABAa Potentiator)
Drug given preoperatively to reduce anxiety
Midazolam (Benzodiazepine) => increase FREQUENCY of Cl- opening at GABAa receptor
Drug that causes Dissociative Anesthesia (altered sense of consciousness but eyes still open) and the MOA
Ketamine: Inhibition of NMDA receptor
- Produces significant analgesia
Used for premedication of mentally challenged/pediatric patients due to many routes of administration
Ketamine
Dexmedetomidine: MOA + Therapeutic indication
MOA: Selective Alpha-2 adrenergic receptor agonist.
Used for short term sedation = therefore intubated/ventilated patients.
General Organ System Effects for IV Anesthetics (Besides Nitrous Oxide and Sevoflurane)
CNS: Depression + Vasoconstrictors
- KETAMINE: Vasodilator therefore increase blood flow
Cardiovascular: Decrease Systemic Blood Pressure
- ETOMIDATE = Modest decrease in systemic BP and minimal effects on HR/contractility
- Ketamine = Transient Increase in systemic BP, HR, and CO.
Respiratory: Depression on ventilation
- DEXMEDETOMIDINE: Moderate decrease/minimal change in respiratory rate.
Drug with systemic effect of vivid colorful dreams, hallucinations, sensory distortions, etc.
Ketamine
