Neuro - Pharmacology (Opiod analgesics)

Question 1

Name 8 opioid analgesics.

Answer 1

(1) Morphine (2) Fentanyl (3) Codeine (4) Loperamide (5) Methadone (6) Meperidine (7) Dextromethorphan (8) Diphenoxylate

Question 2

Detail the mechanism of opioid analgesics.

Answer 2

Act as agonists at opioid receptors (mu = morphine, delta = enkephalin, kappa = dynorphin) to modulate synaptic transmission - open K+ channels, close Ca2+ channels –> decrease synaptic transmission. Inhibit release of ACh, norepinephrine, 5-HT, glutamate, substance P

Question 3

How do opioid analgesics act? Where exactly do they act (give specific receptors)?

Answer 3

Act as agonists at opioid receptors (mu = morphine, delta = enkephalin, kappa = dynorphin)

Question 4

What are 5 substances of which opioid analgesics inhibit the release?

Answer 4

Inhibit release of ACh, norepinephrine, 5-HT, glutamate, substance P.

Question 5

What are 2 clinical uses applicable to all opioid analgesics?

Answer 5

(1) Pain (2) Acute pulmonary edema

Question 6

What is a clinical use for dextromethorphan?

Answer 6

Cough suppression

Question 7

What are 2 opioid analgesics used clinically for diarrhea?

Answer 7

Loperamide and diphenoxylate

Question 8

What is a clinical use for methadone?

Answer 8

Maintenance program for heroin addicts

Question 9

What are 5 toxicities to be associated with opioid analgesics and/or their use with other drugs?

Answer 9

(1) Addiction (2) Respiratory depression (3) Constipation (4) Miosis (pinpoint pupils) (5) Additive CNS depression with other drugs

Question 10

To which 2 toxicities of opioid analgesics does tolerance not develop?

Answer 10

Tolerance does not develop to miosis and constipation

Question 11

How is opioid analgesic toxicity treated?

Answer 11

Toxicity treated with naloxone or naltrexone (opioid receptor antagonist)

Question 12

What kind of drug is butorphanol? Exactly what kind of receptor does it act upon, and how? What effect does this have?

Answer 12

Mu-opioid receptor partial agonist and kappa-opioid receptor agonist; Produces analgesia

Question 13

What is a clinical use for Butorphanol?

Answer 13

Severe pain (migraine, labor, etc.)

Question 14

What is the advantage of Butorphanol over some other opioid analgesics?

Answer 14

Causes less respiratory depression that full opioid agonists

Question 15

What toxicity is associated with Butorphanol, and in what context?

Answer 15

Can cause opioid withdrawal symptoms if patient is also taking full opioid agonist (competition for opioid receptors)

Question 16

What is significant to know about the treatment of Butorphanol toxicity?

Answer 16

Overdose not easily reversed with naloxone

Question 17

What kind of drug is Tramadol? What effects does it have?

Answer 17

Very weak opioid agonist; Also inhibits secretion and norepinephrine reuptake (works on multiple neurotransmitters - “tram it all” in with TRAMADOL)

Question 18

What the clinical use for Tramadol?

Answer 18

Chronic pain

Question 19

How does Tramadaol toxicity compare to that of other opioids? What are 2 other significant toxicities to associate with Tramadol?

Answer 19

Similar to opioids. (1) Decreases seizure threshold (2) Serotonin syndrome