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Pharmacologic Pediatric Pain Management
published in the NHPCO Pediatric Palliative Care
Newsletter, October 18, 2004 |
by John Saroyan
This column was written by John M Saroyan MD, William S Schechter MD, MS,
FAAP and Mary E Tresgallo FNP, RN, MS, MPH. They are from the Pediatric
Pain Management center at Morgan Stanley Children’s Hospital of New
York-Presbyterian.
Are there alternatives to codeine?
Codeine is frequently chosen as a first-line short acting oral opioid.
Morphine, oxycodone, hydrocodone, and hydromorphone are also used. In the
following paragraphs, we present information that will guide you in
choosing between codeine, oxycodone, and hydromorphone and oral morphine;
the four commonly used oral analgesics in our hospital based setting.
Codeine Metabolizers and Non-Metabolizers
Codeine must be converted to morphine by the liver before it can provide
pain relief. Seven to ten percent of the population does not convert
codeine to morphine…meaning seven to ten percent of your patients may
experience the adverse side effects (e.g. nausea, vomiting, constipation)
without the analgesic benefit.
Nausea and Vomiting
If codeine has caused nausea and vomiting in the past, switching to one of
the other drugs may be helpful. Should one always begin with one of these
drugs to avoid the side effects of codeine? All opioids can cause nausea
and vomiting. Codeine may cause more than the alternative drugs. Because
nausea and vomiting are idiosyncratic in children, it is difficult to know
how each child will react.
Metabolism
Codeine is principally metabolized to morphine. Morphine’s major
metabolite M3G, may accumulate in renal failure and cause excitation; the
other major metabolite, M6G, may cause excessive sedation. Oxycodone is
likewise metabolized by the liver. In liver failure, the dose of oxycodone
may have to be reduced or the interval between doses extended. Oxycodone’s
metabolite, oxymorphone, is excreted by the kidney. Oxymorphone can also
accumulate in renal failure and cause neuroexcitation.
Patients with Renal Failure
Hydromorphone should be strongly considered as the opioid of choice in
patients with renal failure. Though hydromorphone’s metabolite is regarded
as inactive, at high doses over time, it too can cause the same
neuroexcitation described above.
Initial PO dosing range Suggested Starting Interval
Codeine 0.5mg/kg to 1 mg/kg Every 4-6 hours
Oxycodone 0.05 mg/kg to 0.1 mg/kg Every 3-4 hours
Hydromorphone 0.03 mg/kg to 0.08 mg/kg Every 3-4 hours
Morphine sulfate 0.3mg/kg Every 4 hours
Availability in Pharmacies
Oxycodone alone is not available in many pharmacies in either liquid or
tablet form. The commercially prepared combination analgesics such as
Percocet (oxycodone 5 mg + acetaminophen 325 mg) are more readily
available. Encourage your pharmacist to stock oxycodone liquid (1 mg/cc)
and 5 mg oxycodone tablets. Oxycodone when given alone can be increased
for pain without the risk of acetaminophen toxicity associated with fixed
dual acetaminophen/opioid preparations (e.g. Percocet, Vicodin).
Twenty-four hour acetaminophen doses should not exceed 30mg/kg, 60mg/kg,
and 90 mg/kg per day in the newborn, infant, and child, respectively. The
adult toxic dose of acetaminophen is 4g/day.
High Concentration Oxycodone Liquid Warning
Commercially prepared oxycodone comes in a concentrated 20mg/cc form
(Oxy-Fast or Oxy-Dose). We recommend using 1 mg/cc concentration for
safety reasons related to safety of administration. It is very easy to
give a large overdose with the concentrated oxycodone if the medication is
drawn up incorrectly. Although all medication should be kept out of the
reach of children, a high concentration of opioid is inadvisable if other
children are living in the home.
The textbook Pain in Infants, Children, and Adolescents, 2nd edition
edited by Schechter, Berde and Yaster, and published in 2003 by Lippincott
Williams and Wilkins is a “must have” for any clinician treating pain in
the pediatric population. Chapter 12 was a valuable source of information
and references for this column.
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