10 - OTC Pain Management Flashcards
What are the two kinds of pain?
Nociceptive
- Somatic
- Visceral
Neuropathic
_____ pain: due to the activation of pain pathways by ongoing tissue damage
Nociceptive
Define somatic pain
- Pain arising in the tissues of the body
- Sharp, sometimes burning, aching, relatively localized
- Osteomyelitis, osteoarthritis, bone fractures
ex. ankle sprain, tooth being pulled out
Define visceral pain
- Pain arising in the organs of a body cavity
- Deep, aching, cramping, diffuse and poorly localized
- Could have nausea, sweating, and CV changes involved (i.e. systemic symptoms)
- Endometriosis (pelvic), Chron’s disease (abdomen), angina (thorax)
- Not often managed with OTC agents (Referral)
Define neuropathic pain
- Caused by direct nerve damage or may be due to abnormal “processing” of a pain signal in the CNS pain pathways due to sensitization of pain neurons
- More commonly chronic, but can be acute
- Can be paroxysmal or spontaneous
- Generally described as burning, tingling, shock-like or shooting
Hyperalgesia
Altered perception such that stimuli which would normally induce a trivial discomfort cause significant pain
Allodynia
Pain due to a stimulus that does not normally evoke pain
Phantom pain
Pain in a limb that is no longer there
Acute Pain:
Cause
Tissue damage often associated with inflammation
Acute Pain:
Duration
Days to weeks (2-4 weeks)
Sub-acute = 4-12 weeks
May depend on the cause
Acute Pain:
Course or prognosis
Predictable
Acute Pain:
Emotional response
Anxiety or overt pain behaviours (grimacing, limping, etc)
Acute Pain:
Treatment
Primarily analgesic
Chronic Pain:
Cause
Neuronal or CNS abnormality (sensitization)
Chronic Pain:
Duration
> 12 weeks (3 months)
Associated with a pattern of recurrence over months or years
May be associated with chronic disease (Rheumatoid arthritis, back pain)
Chronic Pain:
Course or prognosis
Unpredictable
Chronic Pain:
Emotional response
Quiet, depressed
Flat affect
May also have anxiety issues
Chronic Pain:
Treatment?
Multimodal
-Have to try different options, different HCP’s, different therapies, etc.
What is break-through pain?
- Temporary increase in pain to greater than moderate intensity that occurs on a baseline pain of moderate intensity or less
- Causes increased level of psychological distress and significant decrease in function
What is incident pain?
A type of breakthrough pain that is made worse by movement
List some tools for assessing pain
1) Numerical Rating Scale (NRS)
- Patients rate their pain on a scale of 0-10
2) Visual Analogue Scales (VAS)
- 100mm horizontal line, with the left side marked no pain and the right side marked the worst pain
3) Wong-Baker FACES Pain Rating Scales
- Faces ranging from happy to sad based on how they are feeling
* Good for children or people who don’t speak english
What are the 4 main pieces that are essential to pain information gathering?
- Severity of pain
- Location of pain
- Onset and how long the pain lasts
- Quality of pain (description of pain - dull ache, sharp pain, tingling or burning)
What is the role of OTC Pain medication
- Effective when treating mild-moderate somatic pain from skin, muscle and joints
- Also effective in treatment of dysmenorrhea and headache
- Less useful in treatment of visceral pain (refer)
- Effectiveness in neuropathic pain often demonstrates variable response
- Treatment of neuropathic pain may involve a wide range of therapy
List the types of non-prescription pain medications
1) NSAIDs
- ibuprofen
- ASA
- naproxen
2) Acetaminophen
3) Opioids
- Codeine (8mg)
MOA of Acetaminophen?
Produces analgesic effect through central inhibition of PG (fever and pain perception) & peripherally blocking the generation of pain impulses.
- Effective analgesic and antipyretic
- Does not possess anti-inflammatory activity
Oral onset of action for acetaminophen ?
30 minutes
PR onset of action for acetaminophen ?
slowly and incompletely absorbed
Duration of effect for acetaminophen ?
4-6 hours
Acetaminophen:
Adult dosing
325-650 (1000) mg every 4-6 hours
max 4g/day
Acetaminophen is _____-dependent
dose
*meaning that 1000mg produces greater analgesia than 650 or 500 mg dose.
Acetaminophen:
Ceiling effect at ?
1000 mg - no further pain management, just further liver damage
Acetaminophen:
Pediatric dosing
PO: 10-15 mg/kg/dose every 4-6 hours
PR: 15-20 mg/kd/dose every 4-6 hours
Max 65 mg/kg/day (max 5 doses/day)
T or F: Acetaminophen is safe for short term use in children, pregnancy and lactation
true
Describe Acetaminophen Overdose
-It forms a toxic metabolite which is normally detoxified by glutathione. This system can be overwhelmed in an overdose as glutathione becomes depleted (starts to use hepatocyte instead)
What is the minimum toxic single dose in a healthy adult and healthy child?
Adult: 7.5-10g over 8 hours
Child: 150mg/kg over 8 hours
What strategies can be used to prevent accidental or unintentional overdose?
- limit pack size
- change the scheduling
- make font of acetaminophen very large
- just have one strength available for children
- increase patient awareness on the dangers of acetaminophen overdose
Describe the symptoms of Acetaminophen OD
Flu like symptoms
-nausea, vomiting, drowsiness, confusion, sweating (12-24 hours after ingestion)
What is the antidote for Acetaminophen OD and when will you see results from it?
acetylcysteine
-optimal result with antipodal therapy seen within 16-24 hours
Why would an alcoholic have a lower threshold for acetaminophen liver damage?
- possible induction of enzymes
- hepatic dysfunction
- decreased stores of glutathione
*severe liver injury reported in alcoholics who claimed to have taken less than 4g/day
Chronic alcoholism may result in higher blood levels of _____
NAPQ
What is NAPQ?
Acetaminophen metabolite which is toxic to liver cells and reduced blood levels of acetaminophen due to increased metabolism of acetaminophen by CYP2E1
List some non-Rx NSAIDs
ASA
Ibuprofen
Naproxen
What are the pharmacological properties of non-Rx NSAIDs
- Analgesic
- Antiplatelet
- Antipyretic
- Anti-inflammatory