Oral Surgery - Analgesia Flashcards by Erin Murphy

What is the mechanism of action of aspirin?

It inhibits cycle-oxygenase, reduces the production of prostaglandins

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What cyclo-oxygenase is aspirin more effective at inhibiting and what is the effect of this?

COX1
This reduces platelet aggregation
Predisposes to damage of gastric mucosa

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What is the analgesic affect of aspirin

The peripheral action is predominate, it reduces prostaglandin synthesis in inflamed tissues
Reducing pain

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What is the anti-pyretic affect of aspirin

It prevents the temperature rising affects of interleukin-1 and the rise in brain prostaglandin levels

It reduces the elevated temperature in fever

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What is the third affect of aspirin, analgesic, anti-pyretic and ….

Anti inflammatory

Will reduce redness and swelling Aswell as pain a the site of the injury

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What three affects do prostaglandins have on the gastric intestinal mucosa

Inhibit gastric acid secretion
Increase blood flow through the gastric mucosa
Help production of mucins by cells in the stomach lining

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What is the function of gastric mucins

Gastric mucins are components that protect the gastric epithelium from the itch concentrations of Acid in the stomach lumen and from auto digestion by pepsin

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What are three symptoms a patient may experience following an aspirin overdose

Hyperventilation
Deafness
Vasodilation and sweating

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What component of aspirin causes the mucosal burn and why does this happen.

Aspirin applied to locally to the oral mucosa results in a chemical burn, this is a direct result of the salicylic acid.

Aspirin has no topica affect

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Why should aspirin not b given to someone taking warfarin/ anticoagulants

Aspirin enhances warfarin and other anticoagulants

Displaces warfarin from binding sites on plasma proteins, increases the free warfarin.
The majority of warfarin is bound( inactive). If more is realised this will become active increasing bleeding tendency.

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What are thee complications that taking aspirin during pregnancy?

Increased risk of haemorrhage
Increased risk of jaundice in the baby
Can potentially prolong Labour

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Where is aspirin metabolised and where is it excreted

Aspirin is metabolised in the liver and excreted by the kidney

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Where are PGE2 and PGI1 synthesised

PGE2 - Renal medulla
PG1 - glomerulus

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What are three affects of inhibition of renal prostaglandins

Sodium retention
Reduced renal blood flow
Renal failure

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Aspirin is contraindicated in children under 16s years and breastfeeding, what condition is this aiming to prevent

Reyes Sydrome

Fatty degerative process in the liver and profound encephalopathy in the brain

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What is the best way to find out if someone with asthma can take NSAIDS

Ask the patient if they have any hypersensitivity to NSAIDs before or if they have any adverse affects when taking them before

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Why are elderly people in the list of groups to avoid when prescribing NSAIDS

They have a smaller blood volume, they tend to be on other medications and often have other medical issues

Elderly people are most susceptible to drugs induced side affects in general

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What is G6PD deficiecy and what does it make them susceptible to

Glucose 6-phosphonate deficiency - they are at risk of developing acute haemolytic anamia

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Where is G6PD most popular

Most common in individuals orgingating from parts of Asia.Africa/ oceana and southern Europe’s

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What are the 4 groups that NSAIDS are completely contraidnacted in?

Children under 16years; breastfeeding
Previous or active peptic ulceration
Haemophilia
Hypersensitivity to aspirin or any other NSAID

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When prescribing aspirin for mild to moderate odontogenic what is the dosage

300mg 2 tablets 4 times a day

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What is the maximum dosage of aspirin

4grams

If a patient has a hypersensitivity to aspirin or any other NSAID what can be prescribed, what groups would you be wary of when prescribing these?

Lansoprazole 15mg 1 capsule 1 daily
Gastro-resistant omeprazole 20mg 1 capsule 1 daily

Be wary of patients with liver diease, pregnancy or breast feeding

What is the maximum adult dose for ibuprofen

2.4 grams

What is the prescription for ibuprofen

Tablets 400mg 1 tablet 4x daily

Name 4 cautions when prescribing ibuprofen

Previous or active peptic ulcer diease The elderly Pregnancy and lactation Renal, cardiac or hepatic impairment

What is indicated if more than 400mg has been injested within the preceding hour

Activated charcoal followed by symptomatic measures

What is the daily max dose of paracetamol

4g daily 8 tablets

What is the mode of action of paracetamols

Hydroperoxides are generated from the mechanism of the arachidonic acid by COX and activate a positive feedback to stimulate cox activity. This feedback is blocked by paracetamol thus directly inhibiting COX

Why is there little/no gastric mucosal irritation when suing paracetamol?

This is because it does not seem to have much affect on peripheral prostaglandins, is is described as a safe analgesic

What is the main site of action of paracetamol

The thalamus

What amount of paracetamol can cause a potential overdose and what are the effects?

As little as 10-15grams (20-30 tablets) or 150mg/kg of paracetamol a taken wihtin 24 hours can cause severe hepato-cellular necrosis and less free frequently renal tubular necrosis

Why, even if there is a lack of signficant symptoms should a patient who has taken a paracetamol overdose go to hospital immediately

Liver damage is at its maximum 3-4 days after the injection, therefore even if there are a lack of symptoms they should be transferred to hospital

What are the three groups we should have caution when prescribing?

Hepatic impairment Renal impairment Alcohol dependable

Disuss the pathway of pain

Trauma and infection lead to the breakdown of membrane phospholipid producing arachiodonic acid. This arachiodonic acid can then be broken down to produce prostaglandins. Prostaglandins sensitise the tissues too other inflammatory products with results in pain

What is the effect of prostaglandins

Prostaglandins themselves do not cause pain directly, they sensitise the tissues to other inflammatory products such as leukotrines

Name three clinical features of trigeminal neuralgia

Severe spasm of pain; electric shock; lasts a few seconds Usually unilateral Older age group Periods of remission, recurrence often greater severity

What is the starting dose of carbamazepine and how does the treatment progress

Stating dose is usually 100/200mg tablets depending on the patient and then the dose is gradually increased according to responses Usuall dose is 200mg 3-4 daily

Where do opioids act

They act on the spinal cord, mainly in the dorsal horn pathways, central regulation of pain

How do opioids work

They produce their effects via specific receptors which are closely associated with neuronal pathway as that transmit pain to the CNS.

What are the three main problems with opioids

Dependence - psychological and physical. Withdrawal will lead to cravings and the patient will become not well Tolerance - to achieve the same therapeutic affect the dose of the drug needs to be progressively increased Effects on smooth muscle - constipation and urinary and bowel retention

What affect does alcohol have on opiods

It enhances their affect

When the opioid has its effect on the CNS it depresses 4 things;

1. Pain centre - alters awareness and perception of pain 2. Higher centres 3. Respiratory centre 4. Cough centre

What the most common side affects of opioids and what are the side affects of a larger dose

Common - Nausea, vomiting and drowsiness Larger doses can lead to respiratory depression and hypotension

What are the three groups which are contraindicated when using opioids?

Acute respiratory depression Acute alcoholism Raised intracranial pressure/ head injury

Why must you never give someone with raised intracranial pressure or a suspected head injury an opioid?

This interferes with respiration and it affects pupillary responses which are vital for a neurological assessment

What is the composition of paracetamol and codeine in co-codamol

8mg codeine and 500mg of paracetamol

What is the only codeine combination that is on the dental list

Dihydrocodeine

Dentists can only prescribe dihydrocodeine in the oral route, what is the dosage

30mg tablets 4-6 hours

What are the two serious interactions with dihydrocodeine?

Antidepressants MAOIs ( monoamine oxidase inhibitors) Dopaminergics

What is the BNFs stance on opioid use in dentistry and why

Due to the side affects of nausea and vomiting it is of little value for dental pain It is not very effective for post operative pain

What is the antidote for an opioid overdose and when is it indicated

The specific antidote is naloxone and it is indicated when there is a coma or bradypneoa

Why must naloxone be monitored and repeated injections

Because it has a shorter duration of action than many opiods