Transcript Milestones of Acute Pain Medicine at

Prof. Krishna Boddu
.
MBBS, MD, DNB, FANZCA, MMEd
University of Texas Health Sciences at Houston, Texas, USA
University of Western Australia, Perth, Australia
Director, Regional Anaesthesia, Royal Perth Hospital, Perth, Australia
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Patient on Oral Pain medication – Now NPO
Post-Op patient On IV meds. Now on regular diet.
Regional (Epidural/ nerve blocks) to other mode
Drug interaction Eg. Started on Refampin
Drug diversion
Interventional
IV, IM, Sub Q
PO/ NG Tube
PAIN
NPO Status
Tolerance
Other
Activity
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Information from
Patient and Charts
Details of all the
Analgesics in use
Names of the drugs
Routes of administr
Dose, Freq, 24h use
Pharmacodynamics
Information from
Text Books
Bioavailability, Max
dose, Equipotency
& interactions
Onset, duration of
action & peak effect
Wash in & wash out
curves
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Opioids
Non-Opioids
How long the
patient is on these?
Estimated Opioid
Equivalence
available for some
Local Anesthetic
based analgesia
poses challenges
Convert 24 hour
dose to IV MSO4
Equivalent
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Scenario 1: For back pain, for several months patient is on
-100mg of MSContin PO Q8h &
-30mg MSIR Q 4h PRN (uses approx 90mg/day)
-100mg Pregabalin Q8h for neuropathic pain
How to transition to IV PCA? What are the steps?
390mg PO MSO4 in 24h (Actual) =
130mg IV MSO4 in 24h (Estimated)
Per hour IV Morphine use= 5.41mg (Estimated)
Will pt be happy with 1mg dose with LOI 5 min?
(She could get 12mg/h = 288mg MSO4 IV in 24h)
Might be
OK During
the Day
For Sure She
will have
Disturbed Sleep
For Sure She will
wake up with
Severe Pain
NO
WHY?
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You Convince Patient That The Amount of Medication
Available For Her Is Way More Than She Was Taking
At Home to Cover Her Pain.
Now, Patient Requests for Sleeping Pills.
Just because you are giving IV Pain Medication that
too plenty available does not mean that you will be
able to provide better pain control
1-2mg/h MSO4 IV basal on
PCA would be better than
introducing sleeping pills.
What About
Pregabalin?
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Scenario 2 (Surgeon’s request) : Post op pain pt on IV PCA
Hydromorphone & history of heroin abuse ready for transition
to PO pain meds. 24 hour consumption of HM is 30mg.
How to transition to PO meds? What are the steps?
30mg IV Hydromorphone in 24h (Actual) =
150mg IV MSO4 in 24h (Estimated) (based on equi-potency)
600mg PO MSO4 in 24h (Estimated) (based on BA)
Will you be comfortable to give 600mg PO Morphine
to a pt with history of drug abuse?
Will you let What will
the pt
be your
suffer?
concerns?
How to
handle this
situation?
NO
WHY?
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We can not let patient suffer with pain irrespective of his social,
racial, criminal backgrounds.
Our main concern:
How to transition IV to PO and wean off this patient from PO?
Who will priscribe large opioid doses at the time of discharge?
Follow the rules of managing opioid tolerant patient.
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Optimize non-opioid analgesics + Tramadol
Start on alpha 2 agonists clonidine (PO/ TD)
NMDA modulators (Ketamine PO/ IV),
Lidoderm 5% patch
Oxycodone ER with Nalaxone PO 60mg Q8 + 5-10-15 mg
Oxynorm PRN Q4h
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Rationale for Oxycontin & Oxynorm doses
Books say 1.2mg – 2mg Oxycodone = 1mg IV MSO4
Oxycodone
Oxycodone
Bioavailability 80%
Bioavailability 50%
150 mg IV MSO4=
150 mg IV MSO4=
180 mg Oxycodone
300 mg Oxycodone
Give 60% as long acting
60mg Q8h = 120mg
70mg Q8h = 210mg
Remaining dose as PRN in 6 divided doses Q4h
180mg – 120mg = 60mg
300g – 210 mg = 90mg
60mg/6 = 10 mg (Order 5- 90mg/6 = 15 mg (Order
10-15 mg PRN Q 4h)
10-15-20 mg PRN Q 4h)
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3. Transition from Epidural analgesia to IV/PO
Epidural Solution
Opioid + Local Anesthetic
Local Anesthetic
Difficult to convert to
Opioid Equivalence,
so use PRN Opioid
Medication to cover
My Transition Orders
Epidural Solution 8ml/h (LA+
5mcg Hydromorphone/ml
Non-Lipophilic Opioids
1000 mcg IV=
100 mcg Epidural=
10 mcg Spinal
Epidural 50 mcg/h
(1200 mcg/day) =
12000 mcg/day IV
Lipophilic Opioids
1000 mcg IV=
500 mcg Epidural=
250 mcg Spinal
Per day
12 mg IV HM =
55 mg IV MSO4
Stop Epidural after giving first dose of PO Oxycodone 10mg
Paracetamol 1g Q6h (PO/ IV)
Tramadol 100 mg Q 6h (PO/ IV)
NSAID (Celebrex 200 mg BD) / Parecoxib 40 mg Q 8 IV
PRN Oxycodone 5-10-15 mg Q 3h (Mild-moderate-Severe)
If Transition Is Smooth, After 4 h Remove Epidural Catheter
This can be easily
covered with PO
400 mg Tramadol,
4 g Paracetamol,
NSAIDS per day
4. Transition from Nerve Catheter to IV/PO
Remember that it takes only 1-4 hours for block to
disappear after stopping infusion
Local Anesthetic
Difficult to convert to
Opioid Equivalence,
so use PRN Opioid
Medication to cover
My Transition Orders
Stop infusion after giving first dose of PO Oxycodone 20mg
Paracetamol 1g Q6h (PO/ IV)
Tramadol 100 mg Q 6h (PO/ IV)
NSAID (Celebrex 200 mg BD) / Parecoxib 40 mg Q 8 IV
PRN Oxycodone 5-10-15 mg Q 3h (Mild-moderate-Severe)
If Transition Is Smooth, After 4 h Remove Nerve Catheter
5. Drug interaction Eg. Refampin
Complete loss of analgesia possible when pt started on Refampin
With in a day after starting Refampin
Oxymorphone is least influenced by enzyme induction
Do we need to let patient suffer with pain before transition to other?
Close and through followup of APS is required to implement this
Consider optimal non-opioid anagesics + Regional Analgesia
BE AWARE OF ENZYME INHIBITORS & INDUCERS
How to avoid this?
1. In paper form: APS signs to let us know
2. In Electronic Orders: APS as pain medication and build
drug interaction list of your choice
Analgesia fine tuning
First 48h postop or
any pain at rest or
pain all the time
Pain Questions
Give PRN medication
(PRN on PCA, PCEA)
Give meds ATC
(basal on PCA, PCEA)
Only on waking up in
the morning
Night time basal or dose
Pain on activity
Pain not down to
satisfactory level
Pain decreased to
satisfactory level
Relief not lasting
long enough
Increase PRN dose
Consider adjusting ATC dose to keep
60% of 24 hr requirement as ATC
Decrease dose
interval
Requiring frequent PRN > 4 times/ day.
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