Selected Drugs Flashcards
What are examples of Drug Target sites?
Cell membrane receptor sites, nuclear receptors, transport mechanisms, ion channels, enzyme inhibitors
Where are opioid receptors found?
Brain, spinal cord, GI tract
What is an example of an opioid agonist?
Morphine
What are the opioid receptors?
mu, kappa, delta, sigma
What are opioid agonist effects?
Analgesia, miosis (constrict of pupil), cough suppression, sedation, constipation, nauseas & vomiting, rashes & itching, hypotension, respiratory depression, tolerance & dependence. WH
Where in the spinal cords are high in opioid receptors?
Thalamus & dorsal horn
What opioid receptor subtype has the most involvement with analgesia?
Mu
What are the main side effects of opioid agonists?
Respiratory depression, pupil constriction, reduced GI motility, euphoria, dysphoria, sedation, physical dependence
What causes opioid agonist adverse effects?
Unwanted effect are attributable to stimulation of the various sub groups and locations of opioid receptors: therefore difficult to eliminate side effects
What differences between opioid agonists?
All opioid agonists have the same mechanism of action (i.e. opioid receptor agonists) but differ in receptor selectivity, potency, duration of action, metabolism & this determines their clinical use
What are other uses of opioid agonists?
Diarrhoea (loperamide), cough suppression (pholcodine)
What are natural opioids?
Morphine and codeine are naturally occurring opioids
Morphine
Gold standard opioid analgesia, relatively short half-life, available immediate and sustained release
Codeine
Mild to moderate analgesia, anti-diarrhoea agent & cough suppressant. Isa pro-drug - it must be partially metabolised to morphine (active drug) in the liver to have an effect
Oxycodone
Twice as potent as morphine (care with dose conversation), immediate and sustained release
Pethidine
Fast acting, short duration, less respiratory depression. Has toxic metabolite norpethidine
Methadone
long half-life (24 hours) less frequent dosing required, but risk of accumulation. Main agent in opioid substitution therapy
Fentanyl
Fast onset of action, very potent
Buprenorphine
Partial agonist so has an analgesic ceiling as much h less risk of respiratory depression
What is the use of a competitive antagonist in opioid agnostic?
Reversal of opioid overdose. e.g. naloxone
How does tramadol work?
Is a weak agonist for opioid receptors it act principally by inhibition of noradrenaline rey-take and stimulation of serotonin release at nerve synapses in the CNS/spinal cord thus modifying pain impulses to the CNS
What are some side effects of tramadol?
Nausea, dozzine, increased risk of seizures and serotonin syndrome
What are the natural corticosteroids?
Adrenal context produces the natural corticosteroids hydrocortisone (cortisol) and aldosterone
What is hydrocortisone?
A glucocorticoid (it has metabolic, anti-inflammatory and immunosuppressant effects)