Chapter 4 - Pain Flashcards
What is the difference between acute and chronic pain?
Acute - less than 12 weeks
Chronic - more than 12 weeks
How is pain managed in children under 16 years?
Paracetamol or ibuprofen
Switch to the other
Alternate between both
How frequently is paracetamol given?
Every 4-6 hours
Maximum 4 doses per day
How frequently is ibuprofen given?
Every 8 hours
Describe the who analgesic ladder
Step 1. Non-opioids
Step 2. Mild opioids
Step 3. Strong opioids
How frequently should analgesics be reviewed in chronic pain?
At least annually
Is paracetamol:
a) antipyretic
b) anti inflammatory
c) analgesic
a and c
What is the maximum recommended paracetamol dose in
a) >50 kg
b) <50 kg
a) 4g
b) 2g
Why is paracetamol preferred over NSAIDs, especially in the elderly?
Less irritating to the stomach
Less CV and GI complications
What is the maximum pack size of paracetamol that can be sold to the public?
32
What is the maximum number of paracetamol tablets/capsules that can be sold to the public?
100
What are the dangers associated with paracetamol overdose?
Hepatocellular necrosis
Renal tubular necrosis (less common)
What single dosage of paracetamol may cause hepatocellular necrosis?
Generally 10g, or 75mg/kg taken in less than 1 hour
Or 5g if risk factors are present
What are the risk factors for paracetamol overdose?
Alcohol dependency Malnutrition Chronic dehydration Body weight <50kg Severe liver disease Increasing age Concomitant use of hepatic enzyme inducers e.g. rifampin, phenytoin
What are the symptoms associated with paracetamol overdose?
Initially nausea and vomiting
Liver related side effects may occur later
How is paracetamol overdose managed?
If above the treatment line, use IV acetylcysteine
How soon should acetylcysteine ideally be given in paracetamol overdose?
Within 8 hours
NSAIDs have a strong anti-inflammatory action?
Ketoprofen
Piroxicam
NSAIDs have a moderate anti-inflammatory action?
Ibuprofen, naproxen
What is the mechanism of action of NSAIDs?
Inhibit COX-1 and COX-2
What is the effect of inhibiting COX-1 enzymes?
GI irritation due to reducing prostaglandin production
Inhibiting platelet aggregation due to reducing the production of thromboxane A2, so increasing the risk of bleeding
Regulates GFR
What is the effect of inhibiting COX-2 enzymes?
Reduces pain
Reduces inflammation
Reduces fever
What is the main advantage of selective NSAIDS over non-selective NSAIDs?
Reduced GI side effects
What is the main disadvantage of selective NSAIDS over non-selective NSAIDs?
Increased cardiovascular side effects