IV anesthetics

Question 1

What is Dexmedetomidine’s mechanism of action?

Answer 1

Alpha-2 agonist causing sedation, anxiolysis, analgesia, and cardiovascular sympatholysis.

Question 2

How is Dexmedetomidine metabolized?

Answer 2

CYP450 and glucuronidation; NO active metabolites.

Question 3

What are the uses of Dexmedetomidine?

Answer 3

Sedation (dose-dependent, even in non-intubated patients), analgesia, anxiolysis, reduces postoperative shivering and agitation, cardiovascular sympatholytic action.

Question 4

What is the loading dose for Dexmedetomidine?

Answer 4

1 mcg/kg over 10 min.

Question 5

What is the IV infusion dosage for Dexmedetomidine?

Answer 5

0.2-0.7 mcg/kg/hr (up to 24 hrs).

Question 6

What is the onset time for Dexmedetomidine after loading dose?

Answer 6

10-20 min.

Question 7

What is the duration of effect for Dexmedetomidine after stopping infusion?

Answer 7

10-30 min.

Question 8

What are the CNS effects of Dexmedetomidine?

Answer 8

Easily arousable, does NOT interfere with EEG.

Question 9

What are the cardiovascular effects of Dexmedetomidine?

Answer 9

Hypotension, bradycardia; transient hypertension with rapid initial loading dose or high maintenance dose.

Question 10

What are the respiratory effects of Dexmedetomidine?

Answer 10

Does NOT cause respiratory depression; maintains airway reflexes.

Question 11

What is a clinical note regarding Dexmedetomidine?

Answer 11

SPICE III Trial—not associated with reduced mortality in ICU patients.

Question 12

What is Etomidate’s mechanism of action?

Answer 12

GABA modulator.

Question 13

How is Etomidate metabolized?

Answer 13

Rapid hepatic metabolism via ester hydrolysis to INACTIVE metabolites; 10% excreted unchanged in urine.

Question 14

What are the uses of Etomidate?

Answer 14

Induction of anesthesia (especially in cardiovascularly unstable patients), reduces ICP and CBF.

Question 15

What is the dosage for Etomidate?

Answer 15

0.2-0.3 mg/kg IV.

Question 16

What is the onset time for Etomidate?

Answer 16

30-60 sec.

Question 17

What is the duration of effect for Etomidate?

Answer 17

5-15 min (due to redistribution).

Question 18

What are the CNS effects of Etomidate?

Answer 18

Dose-dependent CNS depression, decreases CBF, CMRO2, ICP, and IOP.

Question 19

What are the cardiovascular effects of Etomidate?

Answer 19

Minimal cardiorespiratory depression.

Question 20

What are the respiratory effects of Etomidate?

Answer 20

Less respiratory depression than propofol.

Question 21

What are the adverse effects of Etomidate?

Answer 21

Myoclonia (not seizures), pain on injection, thrombophlebitis, inhibition of adrenal steroidogenesis, nausea and vomiting.

Question 22

What are the contraindications for Etomidate?

Answer 22

Adrenal suppression, porphyria, known hypersensitivity.

Question 23

What is Ketamine’s mechanism of action?

Answer 23

NMDA receptor antagonist; blocks afferent pain signals to the thalamus and cortex.

Question 24

How is Ketamine metabolized?

Answer 24

Liver CYP450, converted to norketamine (active metabolite), then glucuronidated for renal excretion.

Question 25

What are the uses of Ketamine?

Answer 25

Induction of anesthesia in high-risk patients, OB and pediatric anesthesia, analgesia (enhances opioid-induced analgesia, prevents hyperalgesia), non-OR settings (burn units, ER, ICU, radiology procedures).

Question 26

What is the induction dosage for Ketamine?

Answer 26

IV (2-4 mg/kg), IM (4-5 mg/kg), Oral (10 mg/kg).

Question 27

What is the maintenance dosage for Ketamine?

Answer 27

IV infusion (10-45 mcg/kg/min), bolus 0.5-1 mg/kg as needed.

Question 28

What is the onset time for Ketamine?

Answer 28

2-5 min. 30-60 sec

Question 29

What is the duration of effect for Ketamine?

Answer 29

10-20 min.

Question 30

What are the CNS effects of Ketamine?

Answer 30

Dissociative anesthesia (catalepsy, open eyes, nystagmus, intact corneal reflexes); causes emergence hallucinations (common in adults, not kids; treat with benzos or propofol); increases CBF, CMRO2, ICP, and IOP.

Question 31

What are the cardiovascular effects of Ketamine?

Answer 31

Indirect sympathomimetic; increases BP, HR, CO, CVP.

Question 32

What are the respiratory effects of Ketamine?

Answer 32

Potent bronchodilator, preserves airway reflexes.

Question 33

What are the adverse effects of Ketamine?

Answer 33

Salivation, transient apnea with rapid administration.

Question 34

What is Propofol's mechanism of action?

Answer 34

GABA agonist—enhances GABA activity, hyperpolarizing postsynaptic membranes.

Question 35

How is Propofol metabolized?

Answer 35

Rapid hepatic metabolism, redistribution terminates action. 1% excreted unchanged via kidneys.

Question 36

What are the uses of Propofol?

Answer 36

Induction and maintenance of anesthesia, sedation for procedures, used in ECT, cardiac anesthesia, and status epilepticus.

Question 37

What is the induction dosage for Propofol?

Answer 37

1-2 mg/kg IV.

Question 38

What is the maintenance dosage for Propofol?

Answer 38

100-200 mcg/kg/min IV infusion.

Question 39

What is the sedation dosage for Propofol?

Answer 39

25-75 mcg/kg/min IV infusion.

Question 40

What is the onset time for Propofol?

Answer 40

10-50 Seconds.

Question 41

What is the duration of effect for Propofol?

Answer 41

Short (rapid clearance).

Question 42

What are the CNS effects of Propofol?

Answer 42

Decreases CBF, CMRO2, ICP, and IOP; EEG shows delta waves, burst suppression at high doses; provides cerebral protection.

Question 43

What are the cardiovascular effects of Propofol?

Answer 43

Dose-dependent hypotension, reduced CO and SVR.

Question 44

What are the respiratory effects of Propofol?

Answer 44

Significant dose-dependent respiratory depression, apnea.

Question 45

What are the adverse effects of Propofol?

Answer 45

Pain on injection, risk of bacterial contamination; avoid in patients with soy, egg, or fat metabolism disorders; Propofol Infusion Syndrome (PRIS): metabolic acidosis, rhabdo, cardiac/renal failure with prolonged high-dose use (>48 hrs).

Question 46

What is Midazolam's mechanism of action?

Answer 46

Enhances GABA activity.

Question 47

How is Midazolam metabolized?

Answer 47

Hepatic metabolism; effects terminated by redistribution.

Question 48

What are the uses of Midazolam?

Answer 48

Preoperative anxiolysis, sedation, amnesia, anticonvulsant.

Question 49

What is the dosage for Midazolam?

Answer 49

0.1-0.2 mg/kg IV.

Question 50

What is the onset time for Midazolam?

Answer 50

30-60 secs - Rapid.

Question 51

What is the duration of effect for Midazolam?

Answer 51

Short, 15-80 min

Question 52

What are the CNS effects of Midazolam?

Answer 52

Dose-dependent depression, anticonvulsant, amnesia, muscle relaxation.

Question 53

What are the cardiovascular effects of Midazolam?

Answer 53

Minimal effects, but may cause hypotension in elderly or cardiac patients.

Question 54

What are the respiratory effects of Midazolam?

Answer 54

Dose-dependent respiratory depression. Most respiratory depressing among benzos.

Question 55

What are the adverse effects of Midazolam?

Answer 55

Postoperative cognitive dysfunction (especially in elderly), synergistic depression with opioids.

Question 56

What is the reversal agent for Midazolam?

Answer 56

Flumazenil (competitive antagonist), onset 1-2 min, duration 45-90 min.