Ch 28: Opioid Analgesics, Opioid Antagonists, and Nonopioid Centrally Acting Analgesics

Question 1

What are the various effects of opioid agonists?

name 7

Answer 1

analgesia, sedation, respiratory depression,
miosis, constipation, nausea, and suppression of cough reflex

(p. 263 - 264)

Question 2

Very little tolerance develops to which of the 2 effects of opioid agonists?

Answer 2

constipation and miosis

p. 264

Question 3

No cross-tolerance exists between opioids and…

Answer 3

…general CNS depressants such as ethanol, benzos, etc.

p. 264

Question 4

In contrast to withdrawal from general CNS depressants, opioid withdrawal is ______ _________, and lasts _ to __ days.

Answer 4

…rarely dangerous; 7 to 10 days.

p. 265

Question 5

What are two good reasons for NOT using opioids in patients with head injuries?

Answer 5

Morphine can indirectly increase ICP. By suppressing respiration, morphine increases the CO2 content of blood which causes dilation of cerebral vasculature and subsequent elevation of ICP.
Secondly, miosis, mental status changes, and vomiting can be valuable diagnostic signs following head injury. Since morphine causes the same effects, use of opioids can confound diagnosis.

(pp. 263, 265)

Question 6

Morphine can cause toxic megacolon or paralytic ileus in patients with…

Answer 6

…inflammatory bowel disease.

p. 265

Question 7

Agonist-antagonist opioids can precipitate a __________ ________ if given to a patient who is physically dependent on a pure opioid agonist.

Answer 7

withdrawal syndrome

p. 266

Question 8

As a rule, opioids should be administered on a…

Answer 8

…fixed schedule, not PRN.

p. 266

Question 9

When morphine is used for spinal analgesia, which route is preferred?

Answer 9

Epidural is preferred to intrathecal.

p. 267

Question 10

How do intrathecal and epidural doses of opioids compare?

Answer 10

Intrathecal doses are only about one-tenth of the epidural dose.

(p. 267)

Question 11

Which P450 isoenzyme metabolizes fentanyl?

Answer 11

CYP3A4

p. 267

Question 12

The combination of fentanyl plus droperidol is used to produce a state known as…

Answer 12

…neuroleptanalgesia

p. 267

Question 13

What are the major classes of opioid receptors?

Answer 13

Mu, kappa, and delta

p. 281

Question 14

What type of drugs can exacerbate opioid-induced constipation and urinary retention?

Answer 14

anticholinergic drugs

p. 282

Question 15

Use of meperidine should not exceed __ _____, so as to avoid…

Answer 15

…48 hours
accumulation of normeperidine, a toxic metabolite

(p. 282)

Question 16

Most agonist-antagonist opioids act as…

With the exception of buprenorphine (Suboxone) which acts as a…

Answer 16

…agonists at kappa receptors and antagonists at mu receptors.
(p. 282)
…partial agonist at mu receptors and an antagonist at kappa receptors

(p. 273)

Question 17

Why can’t methylnaltrexone (Relistor) reverse the CNS effects of opioids like other opioid antagonists can?

Answer 17

Because it doesn’t cross the blood-brain barrier.

p. 282

Question 18

What is the cough suppression dose for codeine?

Answer 18

10 mg

p. 271

Question 19

Buprenorphine (Suboxone) is a Schedule…

Answer 19

…III drug.

Question 20

Morphine (IV) has a duration of action of…..

…a half-life of….

…and is excreted primarily through…

Answer 20

…..3 to 5 hours….

…2 to 4 hours….

…renal clearance.
It has been suggested that accumulation of morphine-6-glucuronide might cause toxicity with renal insufficiency. All of the metabolites (ie, morphine-3-glucuronide, morphine-6-glucuronide, and normorphine) have been suggested as possible causes of neurotoxicity (e. g., myoclonus).

[Lexicomp]