Flashcards in Pain Deck (120)
Define “pain” as per the International Association for the Study of Pain (IASP).
An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.
List commonly used analgesic drug classes and individual drugs.
What are opiates' mechanism of action?
- What secondary NT system do they act on?
- Which receptor mediates their dependence properties?
Bind mu, delta, and kappa receptors. Cause disinhibition of mesolimbic dopaminergic system (inhibits GABAergic neurons).
- Dependence-producing properties mediated thru mu receptors.
What are some signs and sx of opiate OD?
- Respiratory depression
- Pulmonary edema
- Blue lips
- Unresponsive to stimuli
What are some signs and sx of opiate WITHDRAWAL?
- Sleep disturbances
- Gooseflesh ('cold turkey')
- Involuntary movements ("kicking the habit").
List some STRONG opiates.
List some MODERATE opiates.
- Pentazocine (mild-mod)
List 2 opiate reversal agents.
List the most common NSAIDs.
- Aspirin + salicylates
What is the MoA of traditional NSAIDs?
Nonselective (reversible) inhibition of COX-1 and COX-2
- Celecoxib is COX-2 inhibitor only
Indications for NSAIDs?
Adverse effects of NSAIDs?
- GI/stomach bleeding (5-10% fatality)
- Acute renal failure (from ischemia)
- Increased risk MI + CVA.
When are NSAIDs contraindicated?
- Unique contraindications for ASA?
- GI ulcers
- Bleeding disorders
- Renal disorders (elderly)
- Previous hypersensitivity to ASA (airway compromise in sensitive asthmatics when pts given NSAIDs/ASA)
- Increased risk for CV dz (especially w/celecoxib).
- ASA: children w/febrile viral infections. ASA not typically given to children.
- Gout (inhibits uric acid secretions at low doses).
Antidote to ASA OD?
- Found in Oil of Wintergreen.
What is the MoA behind ASA's anti-platelet function?
Blocks platelet's TXA2 w/o blocking endothelial PGI2
What is the name of the syndrome (and what is it?) that can develop if you give ASA to a child?
Reye's syndrome: often fatal, liver degeneration, encephalitis.
Why is celecoxib sometimes preferred over other NSAIDs?
- What is the downside, and why?
Fewer GI and bleeding toxicities than traditional NSAIDs (still has renal tox.)
- Otherwise not preferable due to increased CVD risk (^ coagulation by blocking endothelial PGI2, not blocking platelet's TXA2)
Which NSAID is mainly used as IV analgesic as a replacement for opioid analgesics?
What is acetaminophen's MoA?
Potent COX-2 inhibitor in CNS, weak COX-1/2 inhibitor in periphery. Stimulates cannabinoid receptors.
What are some indications for acetaminophen?
Fever, pain (NOT anti-platelet or anti-inflam.). Reduces fever/pain in children w/viral infections (avoid Reye's), PUD, hemophilia, and pts w/ASA hypersensitivity
What is behind the toxicity of acetaminophen?
Increased NAPQI, reduced glutathione --> hepatotoxicity.
What is the antidote to acetaminophen OD?
- Effects enhanced by chronic alcohol (induces CYP2E1)
Most common side effects of opiates?
- Constipation, somnolence/mental clouding
- Respiratory depression
- Urinary retention
Kappa opioid receptor agonist (also binds K+ channels, muscarinic receptors, and DA transporters)
Mu and delta opioid receptor agonist, NMDA (glutamate) agonist
MoA of naloxone + naltrexone?
Antagonizes mu, delta, and kappa opioid receptors
What's the difference between the functions of naloxone and naltrexone?
- Naloxone: for opioid OD (reversal)
- Naltrexone: prevents relapse s/p opioid/alcohol detox
Which opiate can cause serotonin syndrome?
Recognize the indications for usage of patient-controlled analgesia (PCA). (5)
1. Post-operative pain
2. Severe acute pain
3. Acute exacerbations of chronic pain
4. Cancer pain
5. Patients unable to take oral medications