Strong opioids Flashcards
Morphine
Choice oral opioid for severe pain in palliative care.
- Also used for coughs in palliative care.
What SE does morphine cause the most?
Euphoria
N + V
Dose
IR = every 4 hours
MR = 12 or 24 hourly
Maximum dose increments = 1/3 or 1/2 of total daily dose per 24 hr
Conversions
Oral –> SC, IV, IM
Half the oral dose
Alternative to morphine
Oxycodone
- More potent
- Similar efficacy/SE profile
- 2 times stronger, therefore give half the morphine dose.
Parenteral route
Diamorphine (heroin)
Preferred over morphine when administering parenterally.
- More soluble
- Smaller volume can be injected in emaciated patients in palliative care
Morphine to diamorphine - conversion
1/3rd of oral morphine dose
What is one benefit of diamorphine
Less nausea and hypotension than morphine
Transdermal route
Long acting
- Buprenorphine
- Fentanyl
Buprenorphine
S/L for opioid dependence
Patches available as:
- 72 hour (3 days)
- 96 hour (4 days)
- 7 days
Buprenorphine - activity
Partial agonist (also has antagonistic properties)
May precipitate withdrawal symptoms, for example in those who are opioid-dependent and were previously taking another opioid.
Fentanyl
72 hour patch
Risk of fatal repi
Buprenorphine - toxicity
Effects are only partially reversed by naloxone in opioid toxicity
Fentanyl MHRA
Risk of fatal respiratory depression in opioid naive patients who have not be previously treated wit a strong opioid
Only use if opioid tolerant
Fentanyl - counselling
Immediately remove patch and seek prompt medical attention if:
- Breathing difficulties
- Marked drowsiness
- Confusion
- Dizziness
- Impaired speech
Fentanyl - switch due to hyperalgesia
Reduce dose of new opioid by 1/4 to 1/2
When is the transdermal route unsuitable?
Acute or rapidly changing pain
- Long time to steady state prevents rapid titration of dose.
- Should only be given when dose and pain is stable
Patches - application
- Apply to dry, non-irritated and non-hairy skin on upper torso or upper arm.
- Rotate patch site after use
- Avoid exposure toe external heat e.g. hot baths, sauna (increased absorption = more SE and toxicity)
