Pain Flashcards
sub-i wards (120 cards)
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.
Morphine Hydromorphone Codeine Fentanyl Oxycodone Hydrocodone Methadone
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?
- Unconsciousness
- Miosis
- Hypotension
- Bradycardia
- Respiratory depression
- Pulmonary edema
- Blue lips
- Unresponsive to stimuli
What are some signs and sx of opiate WITHDRAWAL?
- Anxiety
- Dysphoria
- Craving
- Drug-seeking
- Sleep disturbances
- N/V/D
- Lacrimation
- Rhinorrhea
- Yawning
- Piloerection
- Chills
- Gooseflesh (‘cold turkey’)
- Mydriasis
- Cramps
- Fever
- Involuntary movements (“kicking the habit”).
List some STRONG opiates.
- Meperidine
- Methadone
- Buprenorphine
- Oxymorphone
- Fentanyl
List some MODERATE opiates.
- Oxycodone
- Hydrocodone
- Morphine
- Codeine
- Pentazocine (mild-mod)
List 2 opiate reversal agents.
- Naloxone
- Naltrexone
List the most common NSAIDs.
- Aspirin + salicylates
- Celecoxib
- Ibuprofen
- Naproxen
- Oxaproxin
- Indomethacin
- Diclofenac
- Ketorolac
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?
- Fever
- Pain
- Inflammation
- RA
- OA
- Gout
Adverse effects of NSAIDs?
- GI/stomach bleeding (5-10% fatality)
- Ulcers
- Acute renal failure (from ischemia)
- Bleeding
- 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)
- Pregnancy
- 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?
Sodium bicarbonate.
- 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?
Ketorolac
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?
N-acetyl cysteine.
- Effects enhanced by chronic alcohol (induces CYP2E1)
Most common side effects of opiates?
- Others?
Most common:
- Constipation, somnolence/mental clouding
Others:
- Respiratory depression
- Sedation
- N/V
- Itching
- Urinary retention
Meperidine: MoA?
Kappa opioid receptor agonist (also binds K+ channels, muscarinic receptors, and DA transporters)