Analgesia in Oral Surgery Flashcards
what are the main analgesics used by dental practitioners?
- Aspirin (NSAID)
- Ibuprofen (NSAID)
- Diclofenac (NSAID)
- Paracetamol
- Dihydrocodeine (Opioid)
- Carbamazepine
what must be taken into consideration when prescribing analgesia for a dental patient?
- mechanism of action, blocks pain receptors? anti-inflammatory? etc
- doses (BNF)
- side effects
- interactions
- groups of patient to avoid
how are PROSTAGLANDINS involved in causing pain?
trauma/infection lead to breakdown of membrane phospholipids producing ARACHIDONIC ACID (broken down to PROSTAGLANDINS).
Prostaglandins sensitise tissues to inflammatory products resulting in pain
[therefore, prostaglandin decreases = control the pain]
what are the 3 main properties of aspirin making it effective?
- Analgesic
- Antipyretic (reduce fever)
- Anti-inflammatory
what is the mechanism of action of aspirin? [analgesic action]
INHIBITS cyclo-oxygenases, REDUCING production of PROSTAGLANDINS which means less tissue sensitivity to inflammatory products
[less tissue sensitivity = less pain]
how does the ANTIPYRETIC action work in aspirin?
aspirin prevents temp rising effects of INTERLEUKIN-1 and rise in PROSTAGLANDIN LEVELS in brain. Causing REDUCED ELEVATED temperature in fever cases.
how does the ANTI-INFLAMMATORY action work in aspirin?
reduces production of PROSTAGLANDINS = less tissue sensitivity to inflammatory agents which will reduce and prevent FURTHER inflammation
what are the adverse effects of aspirin?
- git problems (inhibits gastric acid secretion)
- hypersensitivity
- overdose (metabolic acidosis)
- aspirin burns - if left in oral mucosa [scd patients] chemical burn
what groups of patients should AVOID or be CAUTIOUS for aspirin?
- GIT problem patients
- bleeding abnormalities
- patients on steroids
- anticoagulants
- renal/hepatic impaired patients
- hypersensitivity to NSAIDs
- asthma
- children/u16s
what is the ibuprofen dose?
200-400mg orally every 4-6 hours [2.4g MAX 24/HRS]
what are the sideeffects of ibuprofen?
- GIT discomfort (sometimes bleeding/ulceration)
- Hypersensitivity reactions
- headaches, dizziness, renal impairment, hepatic damage, blood disorders
what do you do if a patient has an ibuprofen overdose?
use activated charcoal
what is the main mode of action of paracetamol?
Paracetamol INDIRECTLY inhibits cyclooxygenase (COX) and also reduces prostaglandin preventing pain.
results in:
analgesia
antipyretic action
EXACT MODE OF PARACETAMOL STILL UINCLEAR
what are the main cautions when prescribing paracetamol?
- hepatic impairment
- renal impairment
- alcohol dependence
what is the dose of paracetamol?
500mg-1000mg (4-6 hourly)
MAX DOSE 4G DAILY (8 TABLETS - 1 TABLET 500MG)
Children: depends on weight/age - see BNF
what does a paracetamol overdose cause in a patient?
hepatocellular necrosis -> liver failure -> death
go IMMEDIATELY to hospital
what is an opioid analgesic?
ACTS IN THE SPINAL CORD (CENTRAL REGULATION OF PAIN)
are opioid analgesics effect for dental pain?
BNF states that they are relatively ineffective in dental pain
what are some problems from opiod analgesics?
- Dependence (psychological and physical) - withdrawal
- Tolerance (needs progressively more as body adapts to dose)
what are side effects of opioid analgesics?
effects smooth muscle
- constipation
- urinary & bile retention
most common:
- drowsiness, vomiting, nausea
Larger doses = respiratory depression & hypotension
how do opioids affect the CNS?
depresses:
1. pain centre (alters awareness/perception of pain)
2. higher centres
3. respiratory centres
4. cough centre
how are opioid interactions enhanced?
consumption of alcohol - not good
what are cautions needed when prescribing opioids?
- hypotension
- hypothyroidism
- asthma
- decreased respiratory reserve
- pregnancy/breast feeding
what is carbamazepine?
to treat epilepsy and nerve pain. neuropathic & functional pain - common in dentistry
patients with trigeminal neuralgia?
what is trigeminal neuralgia & clinical features?
a sudden, severe facial pain, described as sharp, shooting or like an electric shock on the trigeminal nerve
- trigger spot identified
- usually unilateral