Opioids II

Question 1

List the clinical uses of opioids

Answer 1

1. analgesia
2. acute pulmonary edema
3. relief of cough
4. diarrhea
5. anesthesia

Question 2

drug interaction: opioid + sedative hypnotics

Answer 2

• increased CNS and respiratory depression

Question 3

drug interaction: opioid + MAO inhibitors

Answer 3

• high incidence of hyperpyrexic coma
  
  • meperidine and dextromethorphan are the worst

Question 4

drug interaction: codeine, oxycodone, and hydrocodone + CYP2D6 inhibitors

Answer 4

inhibit metabolism of these compounds to thier active state

• Fluoxetine is the worst for inhibition

Question 5

contraindications to using opioids

Answer 5

• use of partial agonist with full agonist
  
  • can impair analgesia and cause withdrawal
• head injuries
• pregnancy: especially at delivery
  
  • cross placenta barrier -> respiratory depression or drug dependence of fetus
• impaired pulmonary function
• impaired hepatic or renal function

Question 6

MOA of Morphine

Answer 6

• stimulates all opioid receptors: prototype
• strong agonist : useful in severe pain

Question 7

why is morphine more effective when injected than taken oraly

Answer 7

• high first pass metabolism

Question 8

where is morphine metabolized

Answer 8

• liver by CYP2D6

Question 9

Why should morphine not be given to patients with renal dysfunction

Answer 9

• a major metabolite of morphine can cause adverse effects if it accumulates

Question 10

Why is Hydromorphone better to use than morphine in patients with renal dysfunction

Answer 10

its metabolites don’t accumulate

Question 11

Why is methadone traditionally used for maintenance treatment for addicts

Answer 11

• long lasting, more slowly absorbed
• low doses used to prevent withdrawal

Question 12

MOA of methadone

Answer 12

• stimulates mu receptors
• block NMDA receptors
• now commonly used in long term control of pain

Question 13

MOA of Meperidine

Answer 13

• Mu agonist
  
  • causes euphoria
• inhibits NE/5-HT reuptake -> serotonin syndrome with MAOIs
• blocks muscarinic receptors

Question 14

adverse effects of Meperidine

Answer 14

• should not be used for more than 48 hours, in high doses, or in renal failure due to accumulation of metabolite normeperidine
  
  • ​normeperidine -> seizures
• tachycardia
• pupil dilation
• no cough suppression

Question 15

MOA of Fentanyl

Answer 15

• lipid soluble
• Very potent

Question 16

adverse effects of Fentanyl

Answer 16

• high abuse potential
• truncal rigitidy -> if given rapidly IV
• metabolized by CYP3A4

Question 17

oxycodone + acetaminophen =

Answer 17

percoset

Question 18

oxycodone is metabolized by

Answer 18

• CYP2D6
  
  • needed to be completely effective

Question 19

MOA of Oxymorphone

Answer 19

• active metabolite of oxycodone, used for moderate to severe pain
  
  • does not need to be metabolized by CYP2D6

Question 20

hydrocodone + acetaminophen =

Answer 20

vicodin

Question 21

hydrocodone requires metabolism by what enzyme for full effect

Answer 21

CYP2D6

Question 22

codeine must be metabolized by what to be active

Answer 22

• CYP2D6
• codeine -> morphine

Question 23

codeine is used mainly for

Answer 23

• cough suppressant
  
  • doses lower than for analgesia
  • shouldn’t be used in small children

Question 24

MOA of Pentazocine

Answer 24

• kappa receptor agonist
• Mu receptor partial agonist

Question 25

what is Pentazocine used for

Answer 25

* moderate pain * may be less sedating than other opioids * Low abuse potential, may be good for addicts

Question 26

adverse effects of Pentazocine

Answer 26

* dysphoria (kappa) * may cause withdrawal in patients dependent on opioids

Question 27

MOA of Buprenorphine

Answer 27

* **partial agonist** on **mu** and maybe on **kappa** * ceiling to effect-doesn't cause much euphoria * low abuse potential

Question 28

what is Buprenorphine used for

Answer 28

* maintenance treatment of opioid addiction - decreases craving for drug

Question 29

why is Buprenorphine commonly combined with Naloxone

Answer 29

* tablets are formulated together with naloxone (Suboxone), which is not absorbed sublingually; prevents dissolving the tablets in water and injecting the solution IV

Question 30

MOA of Tramadol

Answer 30

* **Weak Mu agonist** -\> mild to moderate pain * **inhibits NE/5-HT reuptake -\>** contributes to analgesic effect

Question 31

tramadol + antidepressants lead to

Answer 31

seizures

Question 32

tramadol + MAOIs, TCAs, SSRIs may cause

Answer 32

serotonin syndrome

Question 33

MOA of Dextramethorphan

Answer 33

* **blocks NMDA receptors** * **decreases 5-HT reuptake** * **cough suppressant** * not an analgesic

Question 34

Dextramethorphan + MAOIs will cause

Answer 34

serotonin syndrome

Question 35

DOC for opioid overdose

Answer 35

* Naloxone (Narcan) * must be **injected** -\> give until pupils dilate * **short duration of action** (2 hrs)

Question 36

use of Naltrexone

Answer 36

* oral and long acting * used in tx of opioid addicts * if addict takes opioids, won't have any effect * decreases craving in recovering alcoholics

Question 37

Route of admin Naltrexone

Answer 37

PO