Pain Meds Flashcards
(29 cards)
Main function of NSAIDs
Inhibit prostaglandin synthesis by inhibiting cyclooxygenase (COX) 1 and 2
Describe the role of the prostaglandin that COX 1 catalyses
Protective prostaglandins.
Coat the stomach lining in mucus, cause platelet aggregation, regulate renal blood flow
Describe the prostaglandin that COX 2 catalyses
Inflammatory prostaglandins
Increases body temp by acting on hypothalamus, sensitises nociceptors and recruits inflammatory markers towards the injured area of the body
What effect do NSAIDs have on renal blood flow?
Reduced.
This increases exposure time to drugs
What cardiovascular effects do NSAIDs have?
Aspirin limits blood clotting.
All NSAIDs= increase blood pressure
Aspirin has a prolonged effect on platelets and clotting. Explain this.
Aspirin irreversibly inhibits COX 1 in platelets. The platelets do not have their own nucleus, and therefore cannot synthesise new COX 1. Therefore, have to wait for platelet to be turned over / replaced which happens weekly
Basic MOA of aspirin
Irreversibly inhibits COX 1 and 2 (slightly more selective for COX 1)
Compare indomethacin and ibuprofen
Both are competitive, reversible inhibitors of COX 1 and 2
Indomethacin = one of the most potent NSAIDs. Use is limited due to toxicity. Causes more GIT and CV risks than the others.
Ibuprofen = safe for use in children, generally well tolerated
Compare naproxen and diclofenac
Both are competitive, reversible inhibitors of COX 1 and 2
Naproxen = commonly used for period pain. Longer lasting than ibuprofen
Diclofenac = one of the most potent NSAIDs + the longest lasting.
- increased ADRs, commonly co-dosed with antacids
How does paracetamol compare to NSAIDs in terms of efficacy?
Weak anti-inflammatory, good analgesia and much better anti-pyretic
What is the main MOA of SAIDs
They increase the synthesis of annexins (lipocortin 1) which blocks prostaglandin synthesis
Increased BP, cholesterol and blood sugar levels are symptoms of —- name 3 more
Cushing syndrome.
- weight gain
- headaches
- skin thinning
Name an ADR of codeine as a second line treatment for migraines and what can be used to prevent it.
Codeine exacerbates nausea. Can be co-dosed with metoclopramide to reduce nausea and vomiting
Compare COX 1 and 2 and their effect on clotting
Cox 1 = pro-coagulation. (Therefore cox1 blockers = risk of bleeding)
Cox 2 = blocking cox 2 increases risk of clots (therefore, MI and stroke risk)
Narcotics work in the — to suppress pain rather than locally
CNS
Endogenous narcotics =?
Endorphins
Summarise the opioid mechanism of action.
Include: calcium, polarisation and neurons
Activates a GPCR, stopping Ca entry into cell and promoting K efflux. Therefore, hyperpolarises the cell, decreasing neurotransmitters release and neuron excitability
Describe respiratory depression and it’s cause
Reduced CO2 sensitivity in the brain. Meaning increase CO2 levels in blood isn’t recognised and person doesn’t increase breathing rate. Leads to death
Most common side effects of opioids are….
Constipation
Nausea
Hypotension and bradycardia
Opioid antagonist used to reverse respiratory depression
Naloxone
How does methadone work to lessen addiction
Much less euphoria compared to the other opioid agonists
Why is fentanyl delivered via a patch and not IV or oral?
Extremely lipid soluble and easily transported into brain. Extremely potent and longer half life and therefore patch is used for slow delivery
Which opioid, when co-dosed with other opioids, produces an antagonist effect and promotes withdrawal?
Buprenorphine
Rheumatoid arthritis is an autoimmune condition where the immune system attacks the — leading to chronic —
Synovial fluid between joints
Chronic inflammation
