OS- Analgesia Flashcards
When should a patient start taking analgesics?
Before the local anaesthetic wears off
What causes the formation of prostaglandins?
Trauma and infection.
What do prostaglandins do?
They sensitise the tissues to other inflammatory products causing pain.
What do hydroperoxides do?
These exert a positive feedback to stimulate COX activity (used for the production of prostaglandins)
Describe how aspirin works?
It works as an analgesic- inhibiting cyclo-oxygenases (COX-1 & COX-2) to reduce prostaglandin production.
Antipyretic- to prevent:
- the temperature raising effects of interleukin-1
- The rise in brain prostaglandin levels
- The elevated temperature in fever.
Anti-inflammatory- Reduces redness and swelling at the site of injury (by reducing vasodilation and capillary permeability)
Anti-platelet- reduces risk of another myocardial infarction.
Metabolic- It increases base metabolic rate, reducing blood sugar.
What are the side effects of aspirin?
- The reduction in prostaglandins makes patients more likely to develop ulcers and GORD.
- Asymptomatic blood loss from the GIT
- Hypersensitivity reactions
- Overdose- Hyperventillation/ Tinnitus/ Vasodilation and sweating.
- Can cause chemical burns- as it has no topical effect.
What patients should avoid aspirin and why?
Patients with peptic ulcers (as it could cause ulcer perforation)
Patients with bleeding abnormalities (it causes GI bleeding)
Children under 16 (It can cause Reye’s syndrome)
Patients with hypersensitivity to aspirin or other NSAIDS
History of epigastric pain
Those being treated with anticoagulants- (aspirin interacts)
Pregnancy (aspirin may cause impaired platelet function affecting baby)
Patients on steroids (25% of patients on steroids develop a peptic ulcer
Renal/ hepatic impairement (metabolism & excretion problems)
Patients taking other NSAIDs ( combination of NSAIDs increases side effects)
Elderly (are more suceptible to drug induced side effects as they are smaller)
G6PD deficiency- patient is predisposed to blood cells breaking down .
What is reye’s syndrome
Where there is a fatty degenerative process in the liver and swelling in the brain.
It has a 50% mortality rate.
How does aspirin interact with warfarin?
Through displacing warfarin from the binding sites.
This causes an increase in free warfarin which increases the tendency to bleed.
What is the dosage used for prescribing patients with aspirin.
40 x300mg tablets
2 tablets
4 times a day after food
For 5 days
Maximum daily dose- 4g
How does a patient with peptic ulcer disease affect your aspirin prescription?
A protein pump inhibitor should be prescribed for protection
e.g.
5x15mg lansoprazole capsules
1 capsule
once a day.
How does ibruprofen work?
It has a similar effect to aspirin however with a lower risk of gastric mucosa irritation
Discuss the side effects of ibruprofen.
GIT- discomfort/occasional bleeding/ ulceration
hypersensitivity reactions
Overdose.
What patients should avoid ibuprofen?
- Previous or active peptic ulceration
- Elderly
- Pregnancy and lactation
- Renal/cardiac/ hepatic impairement
- History of hypersensitivity to aspirin and other NSAIDs
- Asthma
- Patients taking other NSAIDs
- Patients on long term systemic steroids.
What is the adult dose presrcibed for ibruprofen
20x400mg tablets
1 tablet
4 times a day
5 days
Maximum daily dose 2.4g