pharmacology: opioids

Question 1

effects of morphine

Answer 1

• analgesia (increase pain tolerance and decrease -perception/reaction to pain)
• sedation
• respiratory depression
• vasodilation
• smooth muscle (longitudinal relaxes and circular contricts)
• cough suppression
• nausea and vomiting (stimualtion of chemoreceptor trigger zone)
• increase histamine release

Question 2

what are the effects of morphine on smooth muscle

Answer 2

longitudinal relaxes and circular constricts causing :
GI: decreased peristalsis, constipation, cramping
GU: urinary retention and urgency to void
Biliary: increased pressure
Pupils: miosis

Question 3

what can be used to avoid cramping with opiods?

Answer 3

antimuscarinic (atropine)

Question 4

opiod mechanism

Answer 4

presynaptic and postsynaptic inhibition through Gi coupling (decreased cAMP)
-endorphins effects mu receptor

Question 5

what is the prototype for mu agonist?

Answer 5

morphine

Question 6

what are the full agonists of mu?

Answer 6

morphine, meperidine, methadone, fentanyl, codeine (weak), heroine lol

Question 7

meperidine use

Answer 7

since an antimuscarinic as well - NO MIOSIS, tachcardia, NO spasm GI/GU/gallbladder

Question 8

side effect of meperidine

Answer 8

metabolized by chtochrome P450 to normeperidine which is a serotonin reuptake inhibitors - may cause serotonin syndrome and seizures

Question 9

methadone use

Answer 9

maintenance of opiate addict (long long halflife)

Question 10

codeine use

Answer 10

cough suppressant and analgesia

Question 11

what is the partial opiod agonist? what does it cause?

Answer 11

buprenorphine - causes precipation of withdrawal

Question 12

what are the mixed agonists/antagonist opiods? mechanism and uses?

Answer 12

nalbuphine and pentazocine
kappa agonist for spinal analgesia and dysphoria
mu antagonist causing precipitation of withdrawal

Question 13

what are the opiod antagonists

Answer 13

naloxone, naltrexone, methylnaltrexone

Question 14

naloxone use

Answer 14

IV - reversal for respiratory depression

Question 15

naltrexone use

Answer 15

PO causing decreased craving for alcohol and used in opiate addiction

Question 16

methylnatrexone use

Answer 16

treatment for opioid induced constipation (does not cross BBB and won’t precipitate withdrawal)

Question 17

side effects of opioids

Answer 17

acute toxicity: pinpoint pupils, respiratory depression, coma

Question 18

management of acute toxicity of opioids

Answer 18

supportive and IV naloxone

Question 19

tolerance of opioids

Answer 19

pharmacodynamic (NOT RECEPTOR - but increased cAMP signal transduction)
NO TOLERANCE TO MIOSIS AND CONSTIPATION

Question 20

withdrawal symptoms of opioids

Answer 20

yawning, lacrimation, rhinorrhea, salivation, anxiety, sweating, goose bumps, muscle cramps, spasms, CNS-originating pain

Question 21

management of opioid withdrawal

Answer 21

supportive, methadone, clonidine (alpha 2 agonist - taper down withdrawal symptoms by canceling sympathetic flare up)

Question 22

what opiate-related drug is used for treatment of diarrhea?

Answer 22

loperamide

Question 23

what opiate-related drug is used for treatment of cough?

Answer 23

dextromethorphan