Diamorphine Flashcards
Class
An analgesic - Opioid receptor agonist and mu-opioid agonist
Actions
Analgesia Sedation Euphoria Reduced anxiety Physical/psychological dependence Cough suppression Respiratory depression Increased gut motility
Mechanism of action
Activates u opioid receptors in brain and spinal cord to inhibit pain transmission and modify central perception of pain May inhibit sensory nerve ending activation Opioid receptors are G- protein coupled receptors Open K+ channels and inhibit opening of Ca2+ channels in nerve endings
Clinical use
Moderate to severe chronic and post- operative pain Epidural anaesthesia Neuropathic pain Treatment of painful cough Diarrhoea
Adverse effects
Hypotension Tolerance, dependence and withdrawal effects Larger dose can lead to a coma with respiratory depression
What four endogenous neurotransmitters does Heroin target?
beta-endorphin
dynorphin
leu-enkephalin
met-enkephalin
how does Heroin affect the endogenous opiods?
Reduces and sometimes stops the production of the endogenous opiods
where are endorphines released and what do they do
Endorphins are regularly released in the brain and nerves, attenuating pain.
how does the onset of heroin vary?
onset of heroin’s effects is dependent on the method of administration
onset of oral heroin
Taken orally, heroin is totally metabolized in vivo into morphine before crossing the blood-brain barrier; so the effects are the same as oral morphine
onset of intravenous heroin
Taken by injection, heroin crosses into the brain, where it is rapidly metabolized into morphine by removal of the acetyl groups. It is the morphine molecule that then binds with opioid receptors and produces the subjective effects of the heroin high.
use of diamorphine
Still used clinically, but probably morphine more common in clinical practice.
