Opioids other was corticosteriods Flashcards
What is pain?
What is the gate theory
Draw a diagram show pain control
Give examples of endogenous opioids
Give examples of opiod receptors
state what receptor they are
MOA
µ mu (MOP) δ delta (DOP) κ kappa (KOP)
Mu sounds like muke which sounds like nuke has a K so K+ efflux
Kappa sounds like CAppa
Delta CAMP
Draw a diagram showing how this results in reduced neurotransmitter release from the presynaptic neurone
Adverse Drug Reactions? (Variable with each patient)
most ADRs are due to?
Vomit shortly after - direct stimulation to vomiting centre in the brain
constipation - Nerve plexus inhibited
drowsiness - sedatives/narcosis, induce sleep, problem with work
Smooth muscle relaxants?
hypo - Smooth muscle relaxants?
Pharmacodynamics
Agonist e.g.
Partial agonist e.g.
Mixed agonist/antagonist e.g.
Full antagonist e.g.
Describe the pharmacokinetics for morphine, diamorphine, methadone, buprenorphine
Morphine structure, metabolism, location of action
- multi ring
- Amine group - interacts with binding pocket in opioid receptors
- Hydroxyl molecules at 3 and 6 position - relatively polar groups and makes it more water soluble
Metabolism:
glucuronidation —> Morphine - 6 - glucuronide / Morphine - 3 - glucuronide
(Mu opiod receptor & extends half life)
Metabolites can be measured in urine – screening
What is the half life of diamorphine? And how is it converted into morphine?
Clinical Uses of Opioid Drugs
Main indication (analgesia) - relief of moderate to severe pain (particularly of visceral origin)
Morphine -analgesic (terminal illness), diarrhoea
Diamorphine - analgesic (terminal illness)Doesn’t matter as they will die soon if they develop dependency, epidural analgesia (not licensed)
Methadone - maintenance in dependence
Tramadol - analgesic (5-HT & NA effects)Opioid drug used in Leicester - on immune effector, prevents reputable of 5HT & noradrenaline from synaptic clefts (euphoric effects)
RAISES MOOD
Tapentadol - analgesic (specific μ agonist, and NA reuptake inhibitor)
Clinical Uses of Opioid Drugs
State a mild analgesic
Codeine - mild analgesic (oral) (metabolised to morphine)
Why might patients not get pain relief from codeine?
Clinical Uses of Opioid Drugs
Fentanyl - Anaesthetics
Alfentanil - anaesthetic (ADR: can cause histamine release + morphine ADR)
Remifentanil - anaesthetic (ADR: can cause histamine release + morphine ADR)
100x more potent than morphine
Alfentanil + remifentanil 1000x
But very short half life
Pethidine - analgesia in labour (im) (ADR: resp d & norpethidine (metabolite) -> convulsions)
Do not give frequent repeat doses -> Accumulate in brain and CSF where it will remain active
Opioid agonists-antagonists
- Give examples
- MOA Of nalbuphine
Pentazocine - analgesic
Nalbuphine -
Butorphanol -
Buprenorphine - “ Meptazinol -
- antagonist at µ, partial agonist at κ, weak agonist at δ
Opioid Antagonists examples
Naltrexone derivative of naloxone -> longer half life -> Use: heroin & alcohol addiction
Effects in CNS manly in supraspinatous region - especially in respiratory centres
Indication: patients with opioid overdose and respiratory depression
MOA: two proved stack
Binds to the pockets of receptor to prevent other drugs from bind. INVERSE AGONIST removes any drug that is already bound to the receptor. Rapid onset 3/5 mins and can last as long as an hr.
State the New Endogenous Receptor and Opioid Peptides that bind to it & MOA
Nociceptin opioid peptide receptor with ligand being nocipeptide
Related to kappa receptor
Medico-legal Aspects
Some opioid analgesics are controlled drugs!
The Misuse of Drugs Act 1971
Misuse of Drugs Regulations 2001
Schedule 2: (controlled drugs)
Schedule 5: (controlled drugs)
