Analgesics Flashcards
Which fibre is for mechanical, thermal and chemical. Is myelinated so fast for sharp precise pain
A delta fibres
Pain receptor name
Nociceptor
Which fibre is mechanical, thermal and chemical. Non myelinated so slow for dull burning pain.
C fibres
Which fibre is for pressure, touch and position. Is myelinated so fast for the gate control theory of pain.
A beta fibres
How are nociceptors activated
Inflammation
Action of NSAIDs
Inhibit cox-1 and cox-2
Action of cox-1
Protective effect, secrets gastric acid
Cox-2 action
Causes pain and inflammation
What does NSAID stand for
Non steroidal anti inflammatory drugs
Action pharmacologically on body of NSAIDs
Antipyretic (reduce body temp), analgesic, anti inflam,
Side effects of NSAIDs
Gastric bleeding and ulceration because of cox-1
How to reduce NSAID side effects
Develop drugs that only inhibit cox-2 enzyme e.g. Celecoxib and etoricoxib or give it alongside a protective drug e.g. Misoprostol or omeprazole (ppi) or as a pro drug
Sulindac, nabumetone, fenbufen
NSAID pro drugs
Celecoxib and etoricoxib
Cox-2 specific NSAIDs
Aspirin
Non selective NSAIDs
Warnings of aspirin
Not for under 16’s due to Reye’s syndrome or for ulcer issues or anticoagulants
Ibuprofen (dexibuprofem, fenbufen, ketoprofen)
Non selective NSAID
Why ibuprofen
Less side effects than aspirin but still cause ulcers for prolonged use
Diclofenac, indometacin, mefenamic acid, piroxicam
Alternate ibuprofens
Paracetamol effects
Good antipyretic, analgesic but doesn’t anti inflam
Side effect of paracetamol
Toxic to liver 2-3. Times normal amount
Co-codaprin and co-codamol
NSAIDs + weak analgesic
Use of NSAID and weak opiate combo
Less chance of dependence but doubles the side effects and no greater pain relief
Opium
Opioid analgesic
Action of opium
Euphoria, analgesia and sleep by releasing enkephalins, endorphins and dymorphins and bind to opioid receptors
Morphine
Opioid analgesic
What is codeine, dihydrocodeine and meptazinol for
Mild to moderate pain
What is morphine, diamorphine (heroine), pethidine, buprenorphine and tramadol for
Moderate to severe
What is fentanyl and alfentanil for
Analgesic in surgery
What is the antidote for opioid overdose
Naloxone (prevents the binding)
Side effects of morphines
Constipation (100% of people) , nausea and vomiting/ sedation (30%)
Warning of morphines
Dependence, tolerance, respiratory depression in medulla
Action of local anaesthetics
A delta and c fibres most sensitive cross the membrane and block the Na channels
