Kyle P. Edmonds, MD

Doris A. Howell Palliative Care Consult Service

UC San Diego Health System

PAIN PEARLS & PET PEEVES

2

DR. DORIS A. HOWELL PALLIATIVE CARE CONSULT

SERVICEDr. Doris Howell, pediatric

oncologist.Multi-disciplinary teamFor those with life-threatening disordersComplex CommunicationExpert symptom mgmtClarifying goals of care

OBJECTIVESDescribe the concept of the pain ‘elevator.’List the principles for dosing constant and breakthrough pain.

Name the most common unwanted effect of opioid therapy.

Describe the principle for titration of drips.

International Association for the Study of Pain ( IASP ):

“An unpleasant sensory and emotional experience

associated withactual or potential tissue damage.”

PAIN

5

PEEVE: THE PROCEDURE WASN’T EVEN THAT BAD!

BASIC STEPS: PAIN PROCESSING

TransductionTransmissionPerceptionModulation

7

“TOTAL PAIN”

Pain

Disease Mgmt

Physical

Psych

SocialSpiritual

Practical

EOL Worry

8

PEARL: EXPERIENCES MODULATE PAIN PERCEPTION

9

PEEVE: THEY’RE ON ‘NARCOTICS.’

PAIN MANAGEMENT: DEFINITIONS

Opioid: anything that binds the opioid receptor

Opiate: derived from the opium poppy (Papaver somniferum)

Narcotic: archaic term, associated with illicit use

10

11

PEARL: WE SOUND SMARTER WHEN WE SAY “OPIOID.”

12

PEARL: MEDS ARE CHOSEN BASED UPON LEVEL (AND TYPE) OF PAIN.

GUIDING THERAPY

DiagnosisAssessmentEfficacySafety / tolerabilityEase of useCost

WHO LADDER ELEVATOR

1, Pain 1 – 3

2, Pain 4 – 6

3, Pain 7 – 10

Morphine

Hydromorphone

Fentanyl

OxycodoneMethadone

± Adjuvants

Tramadol

A / Hydrocodone

A / Oxycodone

± AdjuvantsAcetaminophen

NSAID’s

± Adjuvants

WHO. Geneva, 1996.

OPIOID ADVERSE EFFECTS

CommonConstipation

Dry mouthNauseaSedationSweats

UncommonBad dreams / hallucinations

DeliriumMyoclonus / seizurePruritis / urticarialRespiratory depressionUrinary retention

Pla

sma

Co

nce

ntr

atio

n

0 Time

STAGES OF RESPIRATORY DEPRESSION

Sedation

Bradypnea

Death

Awake & in Pain

17

PEARL: RESPIRATORY DEPRESSION IS UNCOMMON IF DOSED PROPERLY.

18

PEEVE: MORPHINE IS TOO STRONG SO I GAVE THEM TWO PERCOCET.

EQUIANALGESIC DOSES

Oral/Rectal Analgesic IV/SC/IM

15 Hydrocodone --

15 Morphine 5

10 Oxycodone --

3 Hydromorphone 1

19

20

PEARL: OPIOID FORMULATIONS DIFFER IN POTENCY.

PAIN MANAGEMENT PRINCIPLES

Don’t delay control Unmanaged pain

nervous system changes

Treat underlying cause

22

BRACE YOURSELVES FOR PHARMACOLOGY.

Pla

sma

Co

nce

ntr

atio

n

0 Time

AbsorptionExcretion

First Order KineticsWhen biological effect

follows plasma concentration

Pla

sma

Co

nce

ntr

atio

n

0

Maximum Concentration ( Cmax )

20

10

= maximum concentration during the dosage interval

Cmax

Time ( hours )

Pla

sma

Co

nce

ntr

atio

n

0 Time ( hours )

Time to MaximumConcentration ( t Cmax )

20

10

1

= time it takes to get to maximum concentration

Cmax MorphinePO / PR

Cmax = 1 hour

Pla

sma

Con

cen

trat

ion

0 Half-life (t1/2) Time

IV

PO / PR

SC / IM

60min

Time to MaximumConcentration ( t Cmax )

30min

10min

Pla

sma

Co

nce

ntr

atio

n

0

Half-Life ( t ½ )

Morphineall routes

t ½ = 4 hours

20

10

= time it takes for the body to excrete half the dose

Time ( hours )4

Pla

sma

Co

nce

ntr

atio

n

0

Dosing every half-life ( t ½ )Oral morphine = 4 hours

164 8 12Time ( hours )20 24

50%75%

87.5%93.75%

97%100%

Pla

sma

Co

nce

ntr

atio

n

0 Time

Steady state after 5 half-livesMorphine ≈ 20 hours

Peak

TroughConcentration

needed to control pain

Concentration where side-effects

start to occur

CONSTANT PAIN DOSING

31

PEARL: FOR CONSTANT PAIN, DOSE MEDICATION EVERY HALF LIFE

32

PEEVE: TITRATING CONTINUOUS DRIPS (OR LONG-ACTING MEDS) TO SYMPTOMS!

Pla

sma

Co

nce

ntr

atio

n

0

Time to Drip Steady State

164 8 12Time ( hours )20 24

50%75%

87.5%93.75%

97%100%

Pain Control

Change GTT

Pla

sma

Co

nce

ntr

atio

n

…20 Time

Steady state forMorphine ≈ 20 hours

Concentration needed to

control pain

Concentration where side-effects

start to occur

35

PEARL: WITH BREAKTHROUGH PAIN, DOSE EVERY C-MAX

Pla

sma

Con

cen

trat

ion

0 Time

Cmax

Breakthrough Pain

PO / PR≈ 1 hr

37

PEARL: SYMPTOMS GUIDE BOLUS DOSING, BOLUS DOSING GUIDES CONTINUOUS DRIP TITRATION.

38

PEEVE: BAD CARTOONS BETWEEN SLIDES

XKCD.COM/1195/

39

PEEVE: THEY DON’T LOOK LIKE THEY’RE IN PAIN!

CHRONIC PAIN

PersistentMay have no obvious cause

Prolonged functional impairment

No sympathetic response

41

PEARL: CHRONIC PAIN LOOKS DIFFERENT THAN ACUTE PAIN.

42

PEEVE: SHE NEEDS MORE AND MORE OPIOID, “SHE IS GETTING ADDICTED.”

43

ABERRANT DRUG-TAKING BEHAVIOR

Desperation over sxsAggressively complainingRequesting specific drugBuying opioids on streetDoctor shoppingPrescription forgery

Passik et al. JClinPain. 2006.

DDX: ABERRANT DRUG TAKING BEHAVIOR

TolerancePhysiologic DependenceDrug DiversionPseudo-addictionAddiction

ADDICTION: HALLMARK

Continued use of drugs in spite of harm

Rare outcome of pain management

46

PEARL: ADDICTION IS NOT A WORD TO BE USED CARELESSLY.

47 BEWARE: MATH AHEAD.

EQUIANALGESIC CONVERSIONS

Metastatic colorectal CA

Stable on OP regimenHere for tune-up prior to AM procedure

EQUIANALGESIC DOSES

Oral/Rectal Analgesic IV/SC/IM

15 Hydrocodone --

15 Morphine 5

10 Oxycodone --

3 Hydromorphone 1

49

SUMMARYMedication choice is driven by severity and type of pain.

It takes 20 hours of constant dosing to reach steady state.

Breakthrough pain dosing should occur on the Cmax.

Around-the-clock dosing should occur on the half-life.

Titrate drips to number and amount of bolus dosing; titrate bolus dosing to symptoms.

50

PAIN PEARLS & PET PEEVES

Kyle P. Edmonds, MDM: 928.853.1483O: 619.471.9424P: 619.290.1212

kpedmonds@ucsd.edu