Opioids / Narcotics

Question 1

Morphine, codeine, oxycodone, and methadone are all opioid analgesics that act on what receptors, and are they agonists or antagonists?

Answer 1

Mu opioid receptors (agonists)

Question 2

Name the 2 major metabolites of morphine. Which one is more active / has higher potency?

Answer 2

M3 and M6; M6 is the active and more potent metabolite

Question 3

Which opioid is commonly used in cough medicine because it is antitussive?

Answer 3

Codeine (morphine is also antitussive; codeine gets metabolized to morphine)

Question 4

A Caucasian patient takes codeine and suffers dry mouth, delirium, urticaria, pruritis, and urinary incontinence, but their pain doesn’t go away. What enzyme might be deficient in this patient, and why is this enzyme needed?

Answer 4

CYP2D6, which converts codeine to morphine (codeine has low receptor affinity so it isn’t a great analgesic anyways)

Question 5

What kind of drugs are tramadol and fentanyl, what receptors do they affect, and are they agonists or antagonists?

Answer 5

Opiods; mu opioid receptor agonists

Question 6

What synthetic analog of codeine inhibits NE and 5HT reuptake as well as the usual actions on mu receptors?

Answer 6

Tramadol

Question 7

What kind of drugs are meperidine and propoxyphene, and why are they no longer recommended for use?

Answer 7

Opiods / mu opioid receptor agonists; not recommended for treating pain due to CNS effects

Question 8

How is fentanyl usualy administered, and what molecular property makes it so potent?

Answer 8

Transdermal patch (long term, long half-life, don’t change dose more than 1x/week); very lipid soluble

Question 9

Which opioid is used to treat heroin addicts? Where does it accumulate in the body?

Answer 9

Methadone; 90% is bound to plasma proteins or accumulates in tissues

Question 10

Which 2 opioids have the longest half lives and greatest risk of overdose? How often can their doses be adjusted?

Answer 10

Fentanyl and methadone; therefore should not change dose more than once a week

Question 11

Diphenoxylate and loperamide are safer analogs of what opioid, and what are they used to treat?

Answer 11

Meperidine; treat diarrhea

Question 12

What 2 effects do diphenoxylate and loperamide have in the body?

Answer 12

They slow peristalsis and decrease intestinal secretions (reduce diarrhea symptoms)

Question 13

Give 3 important side effects of using any opioid.

Answer 13

Miosis, constipation, and respiratory depression

Question 14

What receptors does naloxone affect, is it an agonist or antagonist, and competitive or noncompetitive?

Answer 14

Mu, delta, and kappa opioid receptor antagonist, competitive

Question 15

What receptor does naltrexone affect, is it an agonist or antagonist, and how is the drug used therapeutically?

Answer 15

Mu opioid receptor antagonist; used for alcoholism

Question 16

Nausea, vomiting, piloerection, and yawning are side effects of what kind of reaction to opioids?

Answer 16

These are all side effects of opioid withdrawal, such as after naloxone or naltrexone administration (although opioids themselves can also cause nausea and vomiting…)

Question 17

Does naloxone have a short or long half life, by what route is it therefore administered, and what is it used to treat?

Answer 17

Short; administered by continuous IV; treat acute opioid toxicity