Opioid Drugs [8] Flashcards
Examples of analgesic drugs
Morphine-like (opioids)
Centrally acting non-opioids
NSAIDs
Local anaesthetic
Anticonvulsant
Simple analgesic (paracetamol)
Anti migraine
What is nociception
Process whereby noxious peripheral stimuli are transmitted to CNS
What is the main peripheral sense organ that responds to stimuli
Polymodal nociceptors (PMN)
The majority are non-myelinated C-fibres
How do peripheral nerve fibres cause pain
They have endings in the skin
How is pain added & mediated
Tissue injury causes release of chemicals
They activate receptors
Neurones release substance P which stimulates mast cells & blood vessels
Histamine from mast cells and bradykinin from blood vessels add pain
What are some chemicals that stimulates PMN
Neurotransmitters (5-HT)
Kinins (bradykinin)
Lactic acid
Capsaicin
What is the difference between opioids and opiates
Opioids - drugs with morphine -like effects
Opiates - drugs with close structural similarity to morphine
What antagonises opioids
Naloxone
3 types of opioid
Natural narcotics - opium
Semi-synthetic - heroin
Synthetic - methadone
What is opium
Extract from the juice of poppies
What are the 4 opioid receptors
Mu, delta, kappa, theta
(Theta is for dysphoric effects - hallucinations)
What binds to theta receptors
Benzomorphines
What are mu receptors for
Analgesic effects
Most common receptor
Major unwanted effects include respiratory depression and sedation)
What are delta receptors for
Important in periphery
Also contribute to analgesia
What are kappa receptors for
Contribute to analgesia at the spinal levels
May elicit sedation & dysphoria
