Analgesia Flashcards
1
Q
What systemic analgesics are most relevant to dentistry?
A
- aspirin
- ibuprofen
- diclofenac
- paracetamol
- dihydrocodeine
- carbamazepine
2
Q
How are prostaglandins formed?
A
- trauma and infection lead to breakdown of membrane phospholipids producing arachidonic acid
- arachidonic acid broken down to form prostaglandins
3
Q
What do prostaglandins do?
A
- sensitise the tissues to other inflammatory products
- results in pain
4
Q
What are leukotrienes?
A
- inflammatory mediators
- cause pain and inflammation
5
Q
What is aspirin used for?
A
- effective for dental and TMJ pain
- stroke prevention
- can be bought over the counter
6
Q
What is the mechanism of action of aspirin?
A
- inhibits cyclo-oxygenases (COX-1 & 2)
- more effective at inhibiting COX-1
- reduces platelet aggregation - reduces prostaglandin production
- more effective at inhibiting COX-1
7
Q
What are the properties of aspirin?
A
- anti-inflammatory (NSAID)
- superior to paracetamol
- reduced prostaglandins reduces vasodilation
- analgesic
- peripherally and centrally
- peripheral actions predominate
- due to cycle-oxygenase inhibition
- antipyretic
- prevents temperature raising effects of interleukin-1
- prevents rise in brain prostaglandin levels
- reduces elevated temperature, not normal temperature
8
Q
What are the adverse affects of aspirin?
A
- gastro-intestinal problems
- mainly mucosal lining of stomach
- PGE2 and PGI1
- inhibit gastric acid secretion
- increase blood flow through gastric mucosa
- cytoprotective action, production of mucin cells - most patients will suffer some blood loss from GI tract
- not macroscopically detectable
- asymptomatic
- hypersensitivity
- acute bronchospasm/asthma type attack
- skin rashes
- urticaria (hives)
- angioedema (facial swelling)
- overdose
- tinitus/deafness
- vasodilation and sweating
- metabolic acidosis
- hyperventilation
- coma
- inability to regulate blood pH
- aspirin burns
- mucosal
- when applied locally
- has no topical effect
- must be stalled with water - direct effect of salicylic acid
- mucosal
9
Q
Which groups should be avoided and where should caution be taken prescribing?
A
- care taken in patients with gastrointestinal tract problems
- ulcers
- gastro-oesophageal reflux
- epigastric pain
- peptic ulceration (NEVER)
- can result in perforation
- care prescribing to asthmatics
- ask if any previous issues
- bleeding abnormalities
- haemophilia (NEVER)
- patients taking anticoagulants
- aspirin enhances warfarin and other coumarin anticoagulant activity
- displaces warfarin from binding sites on plasma proteins
- increase free warfarin, increases bleeding tendency
- aspirin enhances warfarin and other coumarin anticoagulant activity
- pregnancy/breast feeding (NEVER)
- especially in third trimester
- impaired platelet function risky near delivery
- increased risk of haemorrhage
- increased risk of jaundice
- can prolong/delay labour - Reye’s syndrome risk if breast feeding
- patients taking steroids
- increased risk of peptic ulcer
- if undiagnosed can result in perforation
- renal/hepatic impairment
- aspirin metabolised in the liver
- mainly excreted in the kidney
- reduced/delayed excretion if impaired - nephrotoxicity
- inhibition of renal prostaglandin synthesis
- sodium retention, reduced renal blood flow
- renal toxicity - interstitial nephritis and hyperkalaemia
- under 16s
- risk of Reyes syndrome
- 50% mortality (brain damage due to encephalopathy)
- rare
- fatty degenerative process in the liver
- profound swelling in the brain
- risk of Reyes syndrome
- hypersensitivity to other NSAIDs (NEVER)
- taking other NSAIDs
- combining will increase risk of side effects
- elderly
- more susceptible to drug induced side effects
- smaller circulating blood volume
- other medical problems and taking medications
- more susceptible to drug induced side effects
- G6PD deficiency
- genetic condition
- enzyme deficiency in red blood cells
- glucose-6-phosphate dehydrogenase
- more susceptible to developing acute haemolytic anaemia
10
Q
What is the recommended dose of aspirin?
A
- 300mg tablets
- 2 tablets, 4 times a day
- prescribed in conjunction in omeprazole
11
Q
What is ibuprofen used for?
A
- post operative analgesia
- following oral surgery
- available as paediatric suspension
- more commonly used in dentistry than aspirin
- similar but not identical effect
- less effect on platelets and irritation to gastric mucosa
- available over the counter
12
Q
What is the mechanism of action for ibuprofen?
A
- inhibits cyclo-oxygenases (COX-1 & 2)
- reduces prostaglandin production
13
Q
What are the properties of ibuprofen?
A
- anti-inflammatory
- analgesic
- antipyretic
14
Q
What are the potential adverse effects of ibuprofen?
A
- gastrointestinal tract discomfort
- occasionally bleeding and ulceration
- hypersensitivity reactions
- rashes
- angioedema
- brinchospams
- other generic side effects
- headache
- dizziness
- nervousness
- depression
- drowsiness
- insomnia
- vertigo
- hearing disturbance/tinitus
- photosensitivity
- haematuria
- blood disorders
- fluid retention
- renal impairment
- hepatic damage
- pancreatitis
- eye changes
- Stevens-Johnson syndrome
15
Q
What groups should not be prescribed ibuprofen and where should care be taken?
A
- previous or active peptic ulceration
- elderly
- pregnant and lactating
- renal, cardiac or hepatic impairment
- history of hypersensitivity to aspirin and other NSAIDs
- asthma
- taking other NSAIDs
- long term systemic steroids
16
Q
What is the recommended dose of ibuprofen?
A
- 400mg tablets
- 1 tablet, 4 times a day (18+)
- reduced for under 18s
- max adult dose is 2.4g
