Pain & Opioids Flashcards
What are some examples of opioid agonists?
Morphine
Methadone
Fentanyl
Codeine
Which opioid is a known opioid partial agonist?
Buprenorphine
What are the 2 known opioid antagonists, and what are they each used for?
Naloxone - for reversing overdoses
Naltrexone - to treat addiction/alcoholism
What is the mechanism of action of tramadol?
It is an Mu opioid agonist, as well as an SNRI
Why does diamorphine have a quicker onset of action than morphine?
Because it is water soluble
What are the drugs involved in the 3 step ladder approach to pain?
Step 1 - paracetamol +/- NSAIDs/adjuvants
Step 2 - step 1 + weak opioid
Step 3 - step 1 + strong opioid
What are some examples of adjuvants in pain?
Tramadol
Amitriptyline
Lidocaine
Gabapentin
Dexamethasone
What are some examples of weak opioids in pain?
Co-codamol
Codeine
Dihydrocodeine
Buprenorphine
What should you do to the dose of paracetamol if the patient is <50kg/malnourished/has hepatic impairment?
Reduce the dose to 1g TDS
Which laxatives are given for opioid induced constipation?
Stimulants, e.g. senna, bisacodyl
What are the side effects of opioids?
Constipation
N+V
Sedation
Respiratory depression
Tolerance
Drowsiness
Rash (itchiness)
What are some characteristics of fentanyl that make it a good opioid?
Very potent
Highly lipophilic so can rapidly absorb in mucosal tissue
Short duration of action - good for break through pain
Lasts up to 3 days
Why should you avoid heat to fentanyl patches?
It can increase the rate of absorption, leading to respiratory depression (SOB/dizziness/confusion)
What is the break through pain conversion of morphine?
x 1/10 -1/6 of the total daily morphine dose
Highest BTP dose would be x 1/6
What is the conversion between oral morphine to diamorphine
Morphine -> diamorphine is x 1/3 (or divided by 3)
