Continued Opioids

Question 1

What is the onset time for Morphine IM injection?

Answer 1

15-30 minutes

Question 2

What is the peak time for Morphine IM injection?

Answer 2

45-90 minutes

Question 3

What is the duration of effect for Morphine IM injection?

Answer 3

4 hours

Question 4

What are the active metabolites formed from Morphine?

Answer 4

Morphine-3-glucuronide and morphine-6-glucuronide

Question 5

How is Morphine eliminated from the body?

Answer 5

Via kidneys

Question 6

What is the metabolism process of Morphine?

Answer 6

Conjugation with glucuronic acid to form morphine-3-glucuronide and morphine-6-glucuronide

Question 7

What Limited CSF Penetration characteristics for morphine?

Answer 7

• Poor lipid solubility
  • Highly ionized at physiological pH (Reason why there’s histamine release = high + charge)
  • Protein binding
  • Rapid glucuronidation

Question 8

What cardiovascular effects can morphine have on supine and normovolemic patients?

Answer 8

Unlikely to experience myocardial depression or hypotension; however, transitioning from supine to standing may cause orthostatic hypotension due to blunted sympathetic tone.

Question 9

What causes bradycardia in patients taking morphine?

Answer 9

Bradycardia is secondary to increased vagal tone in the medulla and decreased conduction in the sinoatrial and atrioventricular nodes.

Question 10

Does morphine sensitize the myocardium to catecholamines?

Answer 10

No, morphine does not sensitize the myocardium to catecholamines; tachycardia and hypertension are related to the pain response.

Question 11

What is a method to prevent histamine release when administering morphine?

Answer 11

Administer no more than 5 mg/minute IV, keep the patient supine or slightly head down, and ensure normovolemia.

Question 12

What is the interaction between morphine and nitrous oxide?

Answer 12

Morphine and nitrous oxide leads to depressed cardiac output and systemic vascular response.

Question 13

What is the interaction between morphine and benzodiazepines?

Answer 13

Morphine and benzodiazepines lead to decreased systemic vascular resistance (SVR).

Question 14

What is the potency of meperidine compared to morphine?

Answer 14

Meperidine has 1/10 the potency of morphine (1 mg of morphine = 10 mg of meperidine).

Question 15

What is the structural similarity of meperidine?

Answer 15

Meperidine is structurally similar to atropine (phenylpiperidine).

Question 16

What is the duration of action for meperidine?

Answer 16

The duration of action for meperidine is 2-4 hours.

Question 17

How is meperidine metabolized?

Answer 17

Meperidine is metabolized in the liver via demethylation to normeperidine and further hydrolysis to meperidinic acid.

Question 18

How is meperidine excreted from the body?

Answer 18

Meperidine is excreted via the kidneys.

Question 19

What is the potency and elimination time of normeperidine?

Answer 19

Normeperidine is ½ the potency of meperidine; elimination takes 15 hours in normal patients and is prolonged to 35 hours in renal patients.

Question 20

What CNS effects can normeperidine cause?

Answer 20

Normeperidine can cause CNS stimulation including myoclonus, seizures, and hallucinations.

Question 21

What effect does meperidine have on post-operative shivering?

Answer 21

Meperidine suppresses post-operative shivering (kappa effect).

Question 22

Is meperidine effective for diarrhea or as an antitussive?

Answer 22

Meperidine is not effective for diarrhea or as an antitussive.

Question 23

What is the potency of fentanyl compared to morphine?

Answer 23

Fentanyl is 75-125 times more potent than morphine (1 mg of morphine = 0.01 mg fentanyl which is 10 mcg).

Question 24

What is the onset and duration of action of fentanyl compared to morphine?

Answer 24

Fentanyl has a more rapid onset and shorter duration of action than morphine.

Question 25

What is the first pass pulmonary uptake of fentanyl?

Answer 25

Fentanyl has extensive first pass pulmonary uptake (75% of dose).

Question 26

How is fentanyl metabolized?

Answer 26

Fentanyl is metabolized by N-demethylation to norfentanyl, which has less analgesic potency.

Question 27

How is fentanyl excreted?

Answer 27

Fentanyl is excreted via the kidneys.

Question 28

What affects the elimination half-life of fentanyl in the elderly?

Answer 28

Prolonged elimination half-life in elderly is due to decreased clearance and decreased available albumin for protein binding.

Question 29

How do sufentanil and alfentanil compare to fentanyl during cardiopulmonary bypass?

Answer 29

Sufentanil and alfentanil show more stable plasma concentrations compared to fentanyl.

Question 30

What is the dosing for fentanyl?

Answer 30

Dosing is 1- 2 mcg/kg (most common dosage) IV for analgesia; 2-20 mcg/kg IV for adjuvant anesthesia; 50-150 mcg/kg for sole anesthesia (rarely used).

Question 31

What are the advantages of Fentanyl?

Answer 31

Lack of direct myocardial depressant effects, no histamine release, suppression of stress response to surgery.

Question 32

What are the disadvantages of Fentanyl?

Answer 32

Failure to prevent sympathetic nervous system responses to painful surgical stimulation, possible patient awareness, postoperative ventilatory depression.

Question 33

What are the routes of administration for Fentanyl?

Answer 33

IM/IV, transmucosal/buccal, transdermal.

Question 34

How is Fentanyl useful in a surgical context?

Answer 34

Useful for preoperative anxiety and facilitates induction of anesthesia; does cause increased risk of pre- and post-op nausea and vomiting.

Question 35

What is the dosage for transdermal Fentanyl patches?

Answer 35

25-100 mcg/hr patches achieve peak concentrations within 18 hours.

Question 36

What is the use of transmucosal/buccal administration?

Answer 36

Useful for preoperative anxiety and facilitate induction of anesthesia.

Question 37

What is a potential risk associated with transmucosal/buccal administration?

Answer 37

Increased risk of pre- and post-op nausea and vomiting.

Question 38

What are the side effects of Fentanyl?

Answer 38

Persistent or recurrent depression of ventilation, blunted carotid sinus baroreceptor reflex to hypotension, seizure activity with rapid IV administration, modest increase in ICP accompanied by decreased MAP and CPP.

Question 39

How does Fentanyl interact with other drugs?

Answer 39

It potentiates the effects of midazolam, particularly hypnosis and depression of ventilation, and decreases the dose requirement of propofol.

Question 40

What is the potency of Sufentanil compared to Fentanyl?

Answer 40

Sufentanil is 5-10 times more potent than Fentanyl (1 mcg of sufentanil = 10 mcg of fentanyl = 1 mg of morphine).

Question 41

What is the half-life of Sufentanil compared to Fentanyl?

Answer 41

Sufentanil has an intermediate half-life between Fentanyl and Alfentanil.

Question 42

What is the onset time for Sufentanil?

Answer 42

Sufentanil has a rapid onset due to lipophilicity (6.2 minutes for sufentanil vs. 6.8 minutes for fentanyl).

Question 43

How is the elimination of Sufentanil affected in the elderly?

Answer 43

Elimination is prolonged in the elderly.

Question 44

What is first-pass pulmonary uptake of Sufentanil?

Answer 44

Sufentanil undergoes first-pass pulmonary uptake (60%).

Question 45

What is the protein binding percentage of Sufentanil compared to Fentanyl?

Answer 45

Sufentanil has higher protein binding than Fentanyl (93% vs. 85% respectively).

Question 46

What effect does low concentrations of alpha1-acid glycoprotein have on neonates?

Answer 46

Low concentrations in neonates lead to ventilatory depression at lower doses.

Question 47

How is Sufentanil metabolized?

Answer 47

It is metabolized in the liver by N-dealkylation and O-demethylation (desmethyl sufentanil has 10% activity of sufentanil).

Question 48

How is Sufentanil excreted?

Answer 48

It is excreted as metabolites via kidneys (<1% unchanged).

Question 49

What is the potency of Alfentanil compared to Fentanyl?

Answer 49

Alfentanil's potency is 1/5 to 1/10 of fentanyl (1 mcg alfentanil = 0.1 mcg fentanyl).

Question 50

What is the duration of action of Alfentanil compared to Fentanyl?

Answer 50

The duration of action of Alfentanil is 1/3 of Fentanyl.

Question 51

What is the onset time of Alfentanil?

Answer 51

Alfentanil has a very rapid onset of action (1.4 minutes vs. around 6 for sufentanil and fentanyl).

Question 52

What is the elimination half-life of Alfentanil?

Answer 52

Alfentanil has a short elimination half-life.

Question 53

How does the lipid solubility and protein binding of Alfentanil compare to Fentanyl?

Answer 53

Alfentanil has lower lipid solubility and higher protein binding than Fentanyl.

Question 54

How is Alfentanil metabolized?

Answer 54

Alfentanil is metabolized in the liver via piperidine N-dealkylation to noralfentanil and amide N-dealkylation to N-phenylpropionamide.

Question 55

What percentage of Alfentanil is cleared from plasma within 60 minutes of administration?

Answer 55

96% of Alfentanil is cleared from plasma within 60 minutes of administration.

Question 56

How is Alfentanil excreted?

Answer 56

Alfentanil is excreted in urine (<0.5% unchanged).

Question 57

What limits the usefulness of Alfentanil?

Answer 57

The usefulness of Alfentanil is limited by interpatient variability (i.e., Cyp 3A4 activity).