Prof. Krishna Boddu Prof. Krishna Boddu . .

MBBS, MD, DNB, FANZCA, MMEdMBBS, MD, DNB, FANZCA, MMEd

University of Texas Health Sciences at Houston, Texas, USAUniversity of Texas Health Sciences at Houston, Texas, USA

University of Western Australia, Perth, AustraliaUniversity of Western Australia, Perth, Australia

Director, Regional Anaesthesia, Royal Perth Hospital, Perth, AustraliaDirector, Regional Anaesthesia, Royal Perth Hospital, Perth, Australia

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1. Patient on Oral Pain medication – Now NPO2. Post-Op patient On IV meds. Now on regular

diet. 3. Regional (Epidural/ nerve blocks) to other

mode4. Drug interaction Eg. Started on Refampin5. Drug diversion

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Interventional IV, IM, Sub Q PO/ NG Tube Other

PAINPAIN ActivityActivityNPO StatusNPO Status ToleranceTolerance

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Details of all the Analgesics in useNames of the drugsRoutes of administrDose, Freq, 24h usePharmacodynami

cs

Information from Patient and Charts

Information from Text BooksBioavailability, Max dose, Equipotency & interactionsOnset, duration of action & peak effectWash in & wash out curves

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How long the patient is on these?Convert 24 hour dose to IV MSO4Equivalent

Opioids Non-OpioidsEstimated Opioid Equivalence available for someLocal Anesthetic based analgesia poses challenges

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

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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)

NOMight be OK During the Day

For Sure She will have Disturbed Sleep

For Sure She will wake up with Severe Pain

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?

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.

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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? NOWill you let the pt suffer?

What will be your concerns?

WHY?How to handle this situation?

We can not let patient suffer with pain irrespective of his social, racial, criminal backgrounds.

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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.

1. Optimize non-opioid analgesics + Tramadol

2. Start on alpha 2 agonists clonidine (PO/ TD)

3. NMDA modulators (Ketamine PO/ IV),

4. Lidoderm 5% patch

5. Oxycodone ER with Nalaxone PO 60mg Q8 + 5-10-15 mg Oxynorm PRN Q4h

Rationale for Oxycontin & Oxynorm doses

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150 mg IV MSO4= 180 mg Oxycodone

Give 60% as long acting60mg Q8h = 120mg 70mg Q8h = 210mg

Oxycodone Bioavailability 80%

180mg – 120mg = 60mg60mg/6 = 10 mg (Order 5-10-15 mg PRN Q 4h)

Remaining dose as PRN in 6 divided doses Q4h

Books say 1.2mg – 2mg Oxycodone = 1mg IV MSO4

150 mg IV MSO4= 300 mg Oxycodone

Oxycodone Bioavailability 50%

300g – 210 mg = 90mg90mg/6 = 15 mg (Order 10-15-20 mg PRN Q 4h)

3. Transition from Epidural analgesia to IV/POEpidural SolutionOpioid + Local Anesthetic

Local Anesthetic Non-Lipophilic Opioids1000 mcg IV=100 mcg Epidural=10 mcg SpinalDifficult to convert to

Opioid Equivalence, so use PRN Opioid Medication to cover

Lipophilic Opioids1000 mcg IV=500 mcg Epidural=250 mcg Spinal

Epidural Solution 8ml/h (LA+5mcg Hydromorphone/ml

Epidural 50 mcg/h(1200 mcg/day) =12000 mcg/day IV

Per day12 mg IV HM = 55 mg IV MSO4

This can be easily covered with PO 400 mg Tramadol, 4 g Paracetamol, NSAIDS per day

My Transition OrdersStop Epidural after giving first dose of PO Oxycodone 10mgParacetamol 1g Q6h (PO/ IV)Tramadol 100 mg Q 6h (PO/ IV)NSAID (Celebrex 200 mg BD) / Parecoxib 40 mg Q 8 IVPRN Oxycodone 5-10-15 mg Q 3h (Mild-moderate-Severe)If Transition Is Smooth, After 4 h Remove Epidural Catheter

4. Transition from Nerve Catheter to IV/PO

Local Anesthetic

Difficult to convert to Opioid Equivalence, so use PRN Opioid Medication to cover

My Transition OrdersStop infusion after giving first dose of PO Oxycodone 20mgParacetamol 1g Q6h (PO/ IV)Tramadol 100 mg Q 6h (PO/ IV)NSAID (Celebrex 200 mg BD) / Parecoxib 40 mg Q 8 IVPRN Oxycodone 5-10-15 mg Q 3h (Mild-moderate-Severe)If Transition Is Smooth, After 4 h Remove Nerve Catheter

Remember that it takes only 1-4 hours for block to disappear after stopping infusion

5. Drug interaction Eg. RefampinComplete loss of analgesia possible when pt started on Refampin

With in a day after starting RefampinOxymorphone is least influenced by enzyme induction

How to avoid this?

1. In paper form: APS signs to let us know2. In Electronic Orders: APS as pain medication and build

drug interaction list of your choice

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

Pain QuestionsFirst 48h postop or any pain at rest or pain all the time

Pain on activity

Give meds ATC(basal on PCA, PCEA)

Give PRN medication(PRN on PCA, PCEA)

Pain not down to satisfactory level

Pain decreased tosatisfactory levelRelief not lasting long enough

Increase PRN dose

Requiring frequent PRN > 4 times/ day.

Decrease dose interval

Consider adjusting ATC dose to keep 60% of 24 hr requirement as ATC

Analgesia fine tuning

Only on waking up in the morning

Night time basal or dose

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