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Methadone taper for opioid-dependent neonates

Opioid analgesics (at VUMC, most frequently fentanyl) are commonly used in surgical neonates for the management of post-operative pain and in infants requiring mechanical ventilation for the treatment of agitation and discomfort.

Neonates who have received significant doses or prolonged infusions of fentanyl will experience opioid withdrawal symptoms if the drug is suddenly discontinued. 50% of neonates who have received > 1.5 mg total dose or an infusion for > 5 days will experience abstinence symptoms; while 100% of neonates receiving a total dose of fentanyl > 2.5 mg or an infusion for > 9 days will withdraw.

When discontinuing narcotics, the drug dosage/infusion rate should be decreased slowly, and infants at significant risk for or with any symptoms of neonatal abstinence syndrome should receive a methadone taper.

Weaning from opioids

The risk of opioid withdrawal increases with the duration and dosage of the opioid infusion. Symptoms of iatrogenic opioid withdrawal can be quantitated using the Neonatal Withdrawal Scoring Inventory in HED.
In an attempt to avoid symptoms of withdrawal, opioids should be weaned slowly. If IV access remains available, there is no need to begin a methadone taper as fentanyl can be tapered until it is discontinued. The duration of any taper, fentanyl or methadone, is patient-specific and may be longer or shorter than the opioid course.

Duration of infusion

< 3 days

3-7 days

> 7 days

Recommended weaning rate

stop or reduce by 50% and stop within 24 hours

reduce by 25-50% of maintenance dose per day

reduce by 10% every 6-12 hours as tolerated

If IV access is no longer needed or desired, a PO methadone taper will be necessary to continue to taper the infant who has been on opioids

There may also be certain circumstances where switching to IV methadone may be indicated, such as in an ELBW infant in which fentanyl would need to be repeatedly diluted during the weaning process

Equivalent Methadone and Fentanyl Dosing for Opioid Weaning

Fentanyl Drip Dose	Starting Methadone Dose IV	Starting Methadone Dose PO
1 mcg/kg/hr	0.03 mg/kg q6hrs	0.05mg/kg q6hrs
2 mcg/kg/hr	0.05 mg/kg q 6 hrs	0.1 mg/kg q 6hrs
3 mcg/kg/hr	0.08 mg/kg q 6hrs	0.15 mg/kg q 6 hrs
4 mcg/kg/hr	0.1mg/kg q 6hrs	0.2 mg/kg q 6 hrs
5 mcg/kg/hr	0.13 mg/kg q 6 hrs	0.25 mg/kg q 6 hrs
6 mcg/kg/hr	0.15 mg/kg q 6 hrs	0.3 mg/kg q 6 hrs
7 mcg/kg/hr	0.18 mg/kg q 6 hrs	0.35 mg/kg q 6 hrs
8-9 mcg/kg/hr	0.2 mg/kg q 6 hrs	0.4 mg/kg q 6 hrs

Standard Methadone Taper

While continuing fentanyl, begin methadone at conversion dose IV or PO q 6 hours.

Also, order a prn dose of methadone for breakthrough agitation: prn dose should be the same as the scheduled dose IV or PO q 2-4 hours.

After the second methadone dose, cut the fentanyl dose in half, and after the fourth dose of methadone, discontinue fentanyl and continue the methadone q 6 hours and prn.

When no prn doses have been needed in a 24 hour period, increase the scheduled dosage interval for methadone to q 8 hours. Continue the prn dose.

When no prn doses have been needed in a 24 hours, increase the scheduled dosage interval for methadone to q 12 hours. Continue the prn dose.

When no prn doses have been needed in a 24 hours, increase the scheduled dosage interval for methadone to q 24 hours. Continue the prn dose.

Once at q 24 hour interval, wean by 10-20% of the original dose every 2-3 days until discontinued. Continue prn dose.

Important Notes:

The prn dose can be given at any time during the intervals between scheduled doses, but wait one hour after giving scheduled dose to give it time for maximal effectiveness.
If more than 3 prn doses have been needed in a 24 hour period, reincorporate the amount of these doses into the 24 hour total and divide the total by the scheduled interval and give this new dose the next 24 hours

References:

Taketomo CK, Hodding JH, Kraus DM. Pediatric Dosage Handbook, 8^th ed. 2001-2002.

Lexi-Comp's Clinical Reference Library, pgs. 422-423