Analgesics for Neuropathic Pain

Question 1

What is the mechanism of action of Ibuprofen?

Answer 1

Inhibits COX 1 and COX 2 (nonselective) and decreases the synthesis of prostaglandins so that the sensitivity to pain fibers is lowered

Question 2

What is the mechanism of action of Celebrex?

Answer 2

Inhibits COX2 (selective) and decreases the synthesis of prostaglandins so that the sensitivity to pain fibers is lowered

Question 3

What is the mechanism of action of aspirin?

Answer 3

In low concentrations (baby aspirin), it inhibits COX1 (selective) and decreases the synthesis of prostaglandins so that the sensitivity to pain fibers is lowered

Question 4

What are predictable side effects of typical nonselective NSAIDs?

Answer 4

1. Inhibition of COX1 causes GI effects= abdominal pain, ulcers, and GI bleeding
2. Inhibition of COX2 causes renal effects= lowered renal blood flow and GFR

Question 5

What are the predictable side effects of aspirin?

Answer 5

Increased risk of bleeding d/t less clotting from antithrombotic effect

Question 6

What are the predictable side effects of celecoxib?

Answer 6

Increased risk of myocardial infarction and stroke d/t more clotting

Question 7

T/F: Acetaminophen is an anti-inflammatory agent

Answer 7

False, possibly from its mechanism involving other unknown pathways outside of COX

Question 8

What are adverse effects seen in acetaminophen?

Answer 8

Liver toxicity

Question 9

What is the mechanism of action opioids?

Answer 9

1. In midbrain: Block release of GABA in periaqueductal gray matter and increase NE and 5-HT so further inhibit pain input
2. In dorsal horn: decrease release of substance P and causes hyperpolarization downstream

Question 10

What opioids are full u (mu) agonists?

Answer 10

Morphine, methadone, fentanyl, and codeine

Question 11

What are the clinical uses of morphine?

Answer 11

Chronic pain (cancer) and Postoperative pain (no PO option for this)

Question 12

What are adverse effects seen with morphine?

Answer 12

Vasodilation and allergic symptoms from increased histamine release on mast cells

Question 13

What are the clinical uses of methadone?

Answer 13

Chronic pain and maintenace drug for opioid dependent patients

Question 14

What are the clinical uses of fentanyl?

Answer 14

used for anesthesia (IV) and in chronic pain (transmucosal, transdermal) and given also bu lozenge (quick onset)

Question 15

What are the clinical uses of codeine?

Answer 15

Used to treat mild to moderate pain (ceiling effect on analgesic efficacy) but caution in CYP polymorphism for effectiveness

Question 16

What drugs are partial u (mu) agonists?

Answer 16

Buprenorphine

Question 17

What are the clinical uses of buprenorphine?

Answer 17

Post-op pain and maintenance drug for opioid dependent patients (long half life)

Question 18

What drugs are opioid antagonists?

Answer 18

Naloxone and naltrexone as these block all opioid receptors

Question 19

What are the clinical uses of naloxone?

Answer 19

Opioid overdose (IM,IV,auto-inj)

Question 20

What are the clinical uses of naltrexone?

Answer 20

Used in opioid dependence (alcohol dependence) and given orally

Question 21

What is the MOA of tramadol?

Answer 21

Weakly stimulate u opioid receptors and inhibit NET/SERT

Question 22

What are clinical uses of tramadol?

Answer 22

Mild to moderate pain (po)

Question 23

What are adverse effects seen in tramadol?

Answer 23

Can cause seizures so use with caution in hx of seizures

Question 24

What is the MOA of clonidine?

Answer 24

Inhibit a2 receptors to decrease substance P neurotransmission

Question 25

What are clinical uses of clonidine?

Answer 25

Post-op pain management and neuropathic pain

Question 26

What are side effects of clonidine?

Answer 26

Hypotension, sedation, and dry mouth

Question 27

What are the clinical uses of gabapentin?

Answer 27

Neuropathic pain and seizures (adjunct therapy)

Question 28

What antiepileptic drugs prolong the inactivated state of Na-channels?

Answer 28

Carbamazepine, phenytoin, and topiramate

Question 29

What are the clinical uses of carbamazepine, phenytoin, and topiramate?

Answer 29

Seizures and neuropathic pain

Question 30

What antidepressants are NET and SERT inhibitors?

Answer 30

Amitriptyline and duloxetine

Question 31

What are the clinical uses of amitriptyline and duloxetine?

Answer 31

Used in depression and neuropathic pain

Question 32

What drugs are voltage gated sodium-channel blockers?

Answer 32

Lidocaine

Question 33

What are the clinical uses of lidocaine?

Answer 33

Used as a local anesthetic and for neuropathic pain (lower concentrations compared to when used as anesthetic)