|
Morphine
vs Hydromorphone vs Oxycodone vs the Fentanyl Patch
Downloadable PDF file
Re-issued by Dr. Doreen Oneschuk, Editor. Grey Nuns Community
Hospital. Original Contributor: Paul Walker, MD - Issue #17
(Collect them all) February, 2004.
The spectrum of available opioids
has increased. Why do we need alternative opioids?
o
Concept of individual variability in opioid response
- relative intensity of analgesic and toxic effects
- spectrum of toxicities experienced
varies with different opioids within the same individual and
between different individuals on the same opioid
May be due to:
•Genetically
- determined expression of opiate receptor subtypes
•Incomplete cross-tolerance
2nd to differential receptor subtype affinity or efficacy
• Opioid metabolite
accumulation
•Pain mechanism
- specific opioid response
Recent proliferation of reports -->improvement in analgesia-toxicity
balance with opioid switch.
Morphine: (immediate release -
Morphine HP, Statex, MOS, MS-IR, Morphitec; slow release - MS
Contin, M-Eslon, MOS-SR, Oramorph SR, Kadian)
• preferred routes:
oral, subcutaneous, rectal
•the standard/benchmark
opioid, usual first choice
•10x more potent
mg for mg than codeine
•parenteral maximum
concentration: 50 mg/ml
Hydromorphone: (immediate release
- Dilaudid, PMS-Hydromorphone; slow release - Hydromorph Contin)
• preferred routes:
oral subcutaneous, rectal
•approx. 5x more
potent mg for mg than morphine
•parenteral maximum
concentration: 100 mg/ml
•the usual alternative
to morphine
Oxycodone: (immediate release
- Supeudol; slow release - OxyContin)
•preferred routes:
oral subcutaneous, rectal
•originally introduced
in combination with ASA (Percodan, Oxycodan, Endodan) or Acetaminophen
(Percocet, Oxycocet, Endocet, Roxicet) for moderate pain.
• hallucinations
reported in studies.
•approx. 1.5x more
potent mg for mg than morphine (controversial)
•parenteral maximum
concentration: 50-60 mg/ml
Fentanyl: (transdermal - Duragesic;
parenteral - Sublimaze)
•high lipid solubility
•50-100x as potent
as morphine
•transdermal patch
convenient in patients with stable pain control. Caution advised
in uncontrolled pain syndromes (not suitable for rapid titration)
• possible in
constipation and sedation
•GI withdrawal syndrome
described with switch to patch
•conversion ratio
uncertain (use published conversion table)
•no convenient form
for rescue doses
•subcutaneous infusions
 pump
needed for continuous infusion high
cost of drug
Consider switching
drug when opioid toxicity develops eg: sedation, delirium,
hallucinations, myoclonus. calculate
an equianalgesic daily dose of the new opioid, reduce this
by 20-30% to account for incomplete cross tolerance between
opioids, divide into multiple daily doses at regular intervals
(q4h for immediate release opioids). Provide approx. 10% of
the total daily dose available as a rescue dose.
REMEMBER: For referrals, questions, or telephone consultations
call 496-1300 weekdays and weekends
|
