Analgesics for Neuropathic Pain Flashcards
What is the mechanism of action of Ibuprofen?
Inhibits COX 1 and COX 2 (nonselective) and decreases the synthesis of prostaglandins so that the sensitivity to pain fibers is lowered
What is the mechanism of action of Celebrex?
Inhibits COX2 (selective) and decreases the synthesis of prostaglandins so that the sensitivity to pain fibers is lowered
What is the mechanism of action of aspirin?
In low concentrations (baby aspirin), it inhibits COX1 (selective) and decreases the synthesis of prostaglandins so that the sensitivity to pain fibers is lowered
What are predictable side effects of typical nonselective NSAIDs?
- Inhibition of COX1 causes GI effects= abdominal pain, ulcers, and GI bleeding
- Inhibition of COX2 causes renal effects= lowered renal blood flow and GFR
What are the predictable side effects of aspirin?
Increased risk of bleeding d/t less clotting from antithrombotic effect
What are the predictable side effects of celecoxib?
Increased risk of myocardial infarction and stroke d/t more clotting
T/F: Acetaminophen is an anti-inflammatory agent
False, possibly from its mechanism involving other unknown pathways outside of COX
What are adverse effects seen in acetaminophen?
Liver toxicity
What is the mechanism of action opioids?
- In midbrain: Block release of GABA in periaqueductal gray matter and increase NE and 5-HT so further inhibit pain input
- In dorsal horn: decrease release of substance P and causes hyperpolarization downstream
What opioids are full u (mu) agonists?
Morphine, methadone, fentanyl, and codeine
What are the clinical uses of morphine?
Chronic pain (cancer) and Postoperative pain (no PO option for this)
What are adverse effects seen with morphine?
Vasodilation and allergic symptoms from increased histamine release on mast cells
What are the clinical uses of methadone?
Chronic pain and maintenace drug for opioid dependent patients
What are the clinical uses of fentanyl?
used for anesthesia (IV) and in chronic pain (transmucosal, transdermal) and given also bu lozenge (quick onset)
What are the clinical uses of codeine?
Used to treat mild to moderate pain (ceiling effect on analgesic efficacy) but caution in CYP polymorphism for effectiveness
What drugs are partial u (mu) agonists?
Buprenorphine
What are the clinical uses of buprenorphine?
Post-op pain and maintenance drug for opioid dependent patients (long half life)
What drugs are opioid antagonists?
Naloxone and naltrexone as these block all opioid receptors
What are the clinical uses of naloxone?
Opioid overdose (IM,IV,auto-inj)
What are the clinical uses of naltrexone?
Used in opioid dependence (alcohol dependence) and given orally
What is the MOA of tramadol?
Weakly stimulate u opioid receptors and inhibit NET/SERT
What are clinical uses of tramadol?
Mild to moderate pain (po)
What are adverse effects seen in tramadol?
Can cause seizures so use with caution in hx of seizures
What is the MOA of clonidine?
Inhibit a2 receptors to decrease substance P neurotransmission
What are clinical uses of clonidine?
Post-op pain management and neuropathic pain
What are side effects of clonidine?
Hypotension, sedation, and dry mouth
What are the clinical uses of gabapentin?
Neuropathic pain and seizures (adjunct therapy)
What antiepileptic drugs prolong the inactivated state of Na-channels?
Carbamazepine, phenytoin, and topiramate
What are the clinical uses of carbamazepine, phenytoin, and topiramate?
Seizures and neuropathic pain
What antidepressants are NET and SERT inhibitors?
Amitriptyline and duloxetine
What are the clinical uses of amitriptyline and duloxetine?
Used in depression and neuropathic pain
What drugs are voltage gated sodium-channel blockers?
Lidocaine
What are the clinical uses of lidocaine?
Used as a local anesthetic and for neuropathic pain (lower concentrations compared to when used as anesthetic)
