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
17
Q
What are the potential drug interactions with ibuprofen
A
- ACE inhibitors
- other analgesics
- antibiotics
- anticoagulants
- antidepressants
- antidiabetics
- corticosteroids
- cytotoxics
- diuretics
- beta-blockers
- calcium channel blockers
- cardiac glycosides
- ciclosporin
- clonidine
- clopidogrel
- lithium
- tacrolimus
- vasodilator antihypertensives
18
Q
What are the symptoms of ibuprofen overdose and how is it managed?
A
- symptoms
- nausea
- vomiting
- tinitus
- management
- activated charcoal
- systemic measures if more than 400mg/kg ingested within an hour
19
Q
What is the mechanism of action of paracetamol?
A
- inhibition of hydroperoxides
- generated from arachidonic acid
- stimulate COX activity
- indirect inhibition of COX
- especially in brain
- main site of action is thalamus
- does not affect peripheral prostaglandins
- little to no gastric mucosal irritation
20
Q
What are the properties of paracetamol?
A
- analgesic
- antipyretic
21
Q
What are the potential adverse effects of paracetamol?
A
- rashes
- blood disorders
- hypotension
- reported on infusion
- liver damage
- less frequently kidney damage
- following overdose
22
Q
What groups should not be prescribed paracetamol and where should caution be taken?
A
- hepatic impairment
- renal impairment
- alcohol dependence
23
Q
What are the potential drug interactions with paracetamol?
A
- anticoagulants (extended use enhances coumarin effect)
- cytotoxics
- domperidone
- lipid regulating drugs
- metoclopramide
24
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
25
Q
What are the symptoms of paracetamol overdose and how is it managed?
A
- hepatocellular necrosis
- maximal 3-4 days after ingestion
- lack of early symptoms - liver failure resulting in death
- maximal 3-4 days after ingestion
- renal tubular necrosis
- less frequently
26
Q
How do opioid analgesics work?
A
- act in the spinal cord
- especially in dorsal horn pathways
- central regulation of pain
- specific receptors closely associated with neuronal pathways transmitting pain to CNS
- relatively ineffective in dental pain
27
Q
What problems do opioids pose?
A
- dependence
- psychological and physical
- withdrawal leads to psychological cravings and physical illness
- tolerance
- dose requires progressive increase
- effect on smooth muscle
- constipation
- urinary and bile retention
28
Q
What problems do opioids pose?
A
- dependence
- psychological and physical
- withdrawal leads to psychological cravings and physical illness
- tolerance
- dose requires progressive increase
- effect on smooth muscle
- constipation
- urinary and bile retention
- effect enhanced by alcohol
29
Q
What are the side effects of opioids?
A
- nausea
- vomiting
- drowsiness
- respiratory depression
- hypotension
- dry mouth
- sweating
- facial flushing
- headache
- vertigo
- bradycardia
- rashes
- urticaria
- pruritus
- palpitations
- hallucinations
- dysphoria
- mood changes
- dependence
- tachycardia
30
Q
What groups should not be prescribed opioids and where should caution be taken?
A
- hypotension
- hypothyroidism
- asthma
- decreased respiratory rate
- pregnancy and breast feeding
- hepatic impairment
- can precipitate coma
- renal impairment
- elderly and debilitated
- convulsive disorders
- dependence
- acute respiratory depression
- acute alcoholism
- raised intracranial pressure/head injury
- interferes with respiration
- affects pupillary responses vital for neurological assessment
31
Q
What is codeine and how is it administered ?
A
- natural alkaloid found in opium poppy
- 1/12th potency of morphine
- low dependence
- effective orally
- usually combined with NSAIDs or paracetamol
- available over the counter
32
Q
What codeine can be prescribed by a dentist and what is it used for?
A
- dihydrocodeine
- moderate to severe pain
- not very effective for dental pain
33
Q
What is the dose for dihydrocodeine and how is it administered?
A
- oral dose
- 30mg every 4-6 hours as necessary
- out with scope of dentistry
- intramuscular and subcutaneousavailable
- 40mg, 60mg and 120mg available
34
Q
What are the side effects of dihydrocodeine?
A
- nausea
- vomiting
- constipation
- drowsiness
- respiratory depression
- hypotension
35
Q
What drugs interact with dihydrocodeine?
A
- antidepressants
- monoamine oxidase inhibitors (MAOIs)
- dopaminergic (Parkinsonism)
36
Q
What groups should not be prescribed dihydrocodeine and where should caution be taken?
A
- hypotension
- asthma
- pregnancy and lactation
- renal and hepatic disease
- elderly
- children
- raised inter cranial pressure/suspected head injury
37
Q
What are the symptoms of opioid overdose and how is it managed?
A
- coma
- respiratory depression
- pinpoint pupils
- antidote is naloxone
- use indicated by coma or bradypnoae
- short duration of action (short half life)
- close monitoring and repeat administration
38
Q
What drug is used for neuropathic and functional pain?
A
- carbamazepine
- trigeminal neuralgia
- post-herpetic neuralgia
- TMJ or atypical face pain
39
Q
What type of drug is carbamazepine?
A
- anticonvulsant
- tegretol
40
Q
What are the clinical features of trigeminal neuralgia?
A
- severe spasms of electric shock like pain, lasting a few seconds
- usually unilateral
- older age group
- trigger spots may be identified
- more common in females than males
- periods of remission
- recurrences often of greater severity
41
Q
What is the recommended dose of carbamazepine?
A
- usual dose is 200mg, 2-4 times daily
- 100-200mg tablets
- once or twice daily
- gradually increase dose according to response
- up to 1.6 g in some patients
