Opioid Weaning/Conversions

What are short acing opioids?

oxycodone, morphine, hydromorphone

-every 4 to 6 hours

What are long acting opioids?

methadone, fentanyl patches, oxycodone ER

-every 8-12 hours

How to initiate opioids onto opioid naive patients?

-Use short acting initially

-Low dose short acting on schedule with extra for breakthrough pain

How to switch short to long acting in patients?

-increase scheduled doses until no breakthrough doses are needed

-then convert to long acting products

Method for opioid conversion

1. proper pain assessment

2. calculate TDD

3. determine opioid change

4. just new dose to fit patient needs

5. ensure new dose is right

6. provide close monitoring or follow up

Routine for converting po to iv

-assess the pain

-calculate the TDD

-convert IV TDD

-evenly spread over 24 hours

When does breakthrough pain occur?

-spontaneous or without warning

-incidental (voluntary or involuntary)

-End of dose

Steps to treat breakthrough pain

1. non-opioid agents

(RICE, TENS unit, nerve based agents, OTC)

2. Breakthrough meds prior to voluntary movement

3. Stick with same opioid when using short/long acting

4. Excessive breakthrough med use should indicate to increase basal coverage

How to calculate breakthrough meds?

10-15% of total daily dose

what is incomplete cross tolerance?

-only when changing opioid types

-reduce TDD by 25-50%

Steps to convert opioids

-assess the pain

-calculate TDD

-covert regarding opioid table

-reduce new TDD by 25-50%

-calculate breakthrough if needed

Key points for fentanyl patches

-75-100 times more potent than morphine

-max conc. at 36 hours

-lasts in skin 24 hours after removal

-cannot use in malnourished or frail

-avoid heat

What is the conversion for morphine and fentanyl?

2 mg morphine : 1 mcg fentanyl

Considerations when converting to fentanyl patched

Cover 12 hour window for fentanyl to become detectable with breakthrough meds until 12 hour is hit

-only convert to and from morphine

-ONLY OPIOID TOLERANT PATIENTS

Steps to convert to fentanyl

-Assess pain

-Calculate TDD

-Convert to morphine if needed

-Covert to fentanyl

-Apply patch at next dose of long acting opioid

-Follow up

Points converting from Fentanyl

-first 12 hours use breakthrough meds only

-next 12 hours use 50% of calculated new dose

-after 24 hours use 10% of new dose

Key points of Methadone

-Less euphoria than other opioids

-mu, kappa, delta agonist

-SSRI/SNRI and NMDA antagonist activity

-detectable 20 minutes after taking

-no dose changes 5-7 days

-QTc prolongation

Baseline EKG ranges for methadone

<450 is safe

450-499 monitor

>500 avoid or decrease

Points for Methadone Conversion

-use 10:1 ratio

-only convert from morphine

-baseline 2.5 mg every 12 hours

-CYP3A4 med caution (inducers may need to increase dose)

Morphine methadone ratio

Going back to morphine

3mg morphine to 1 mg methadone

Points for starting Methadone

-hard change

-all opioid should be stopped unless short acting not in conversion

-follow up one week

How to increase methadone if stable?

increase at one week by 25-50%

When to avoid methadone

-poor/limited prognosis

-non compliance

-excessive fatigue and sedation

-live alone

-QTc>500

Methadone counseling points

-sedation

-take religiously

-do not adjust on own

-wait 5-7 days for response

Important consideration during opioid weaning

-Half-life, TDD, and duration

-psychosocial support prior/during wean

-be flexible during process

-can take months