Analgesia Flashcards
What drugs can dentists prescribe
CHECK DENTAL PRACTITIONERS FORMULARY IN BNF
Aspirin, ibuprofen, diclofenac (NSAIDs), paracetamol, dihydrocodeine, carbamazepine
Arachidonic acid pathway
Trauma and infection> breakdown of membrane phospholipids> arachidonic acid
Arachidonic acid broken down to form prostaglandins
These sensitise tissues to other inflammatory products> PAIN
What do prostaglandins do
Do not cause pain directly
Sensitise tissues to other inflammatory products
E.g leukotrienes
Prostaglandin production decrease=moderation in pain
Aspirin (acetylsalicylic acid) properties
Effective for dental and TMJ pain
Analgesic, antipyretic, anti-inflammatory
Mechanism of action of aspirin
Inhibits COX 1+2 (more COX 1)
Therefore reduces production of prostaglandins
COX 1 inhibition reduces platelet aggregation
Analgesic properties of aspirin
Work peripherally and centrally
More peripheral
Analgesic action from inhibition of prostaglandin synthesis (from COX inhibition)
Antipyretic properties of aspirin
Prevents temp raising effects of interleukin 1 and rise in brain prostaglandin levels
Reduces ELEVATED temp
Anti-inflammatory properties of aspirin
Vasodilation, affect capillary permeability
Will reduce redness, swelling and pain at site
Adverse effects of aspirin
GIT problems
Hypersensitivity
Overdose- tinnitus, metabolic acidosis
Aspirin burns- mucosal
What is metabolic acidosis
Can’t regulate blood pH
When is aspirin completely contraindicated
Children and adults under 16, REYES SYNDROME
Previous of active peptic ulceration
Haemophilia
Hypersensitivity to aspirin or any other NSAID
How to avoid aspirin burn
Take aspirin with water
Aspirin and anticoagulants
Enhances warfarin and other anticoagulants
Increased bleeding tendency (as most warfarin is bound an inactive)
Aspirin and children under 16
N.B Breastfeeding
Can cause Reye’s syndrome- up to 50% mortality
fatty degenerative process in liver, swelling in brain
If pt with odontogenic pain has prev or active peptic ulcer disease and requires NSAID (paracetamol ineffective), what do you prescribe?
Proton Pump inhibitor (e.g. omeprazole)
Ibuprofen properties
NSAID
More commonly used
Long term use recently associated with increased risk of cardiac events
Paeds suspension available
Ibuprofen max dose
2.4g
Ibuprofen side effect
GIT discomfort (bleeding, ulceration), hypersensitivity, headaches, dizziness…
Caution when prescribing ibuprofen
Prev or active peptic ulceration
Elderly
Pregnant …
Ibuprofen overdose
Nausea, vomiting, tinnitus
Activated charcoal if more than 400mg/kg ingested in last hour (two tablets= 400mg)
Paracetamol properties
Analgesic
Antipyretic
LITTLE OR NO ANTI-INFLAMMATORY ACTION
No effects on bleeding time
No significant interaction with warfarin
Less irritant to GIT
Suitable for children
How does paracetamol work
Hyperoxides are produced from metabolism of arachidonic acid by COX
COX then exert positive feedback to stimulate further COX activity
This feedback is blocked by paracetamol
What does the positive feedback inhibition action of paracetamol result in
Analgesia
Antipyretic action
No reduction of peripheral inflammation
Where is main site of action of paracetamol
Thalamus
