THE RESIDENT’S GUIDE TO PAIN MANAGEMENT

Elizabeth Kvale, MDPalliative Medicine

THE AMERICAN GERIATRICS SOCIETY

Geriatrics Health Professionals.

Leading change. Improving care for older adults.

AGS

PAIN PHYSIOLOGY BASICS:TYPES OF PAIN

• Nociceptive — arthritis, fracture, laceration

• Visceral — pancreatitis, MI, constipation

• Neuropathic — herpes zoster, diabetic neuropathy

• Complex regional pain syndromes (RSD)

• Central pain

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PAIN PHYSIOLOGY BASICS:ACUTE VS. CHRONIC PAIN

Acute pain• Identified event, resolves

in days–weeks• Usually nociceptive

Chronic pain• Cause often not easily

identified; multifactorial• Indeterminate duration• Nociceptive and/or

neuropathic

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PAIN ASSESSMENT BASICS:BELIEVE THE PATIENT

• Pain is a subjective experience ― the patient is the best source of information about their pain

• Pain history ― site(s), intensity, temporality, character, exacerbating and alleviating factors

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PAIN ASSESSMENT BASICS:USE AN ASSESSMENT INSTRUMENT

Allows you to know and document whether you have helped the patient

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Match the medication to the amount of the patient’s discomfort

PAIN MANAGEMENT BASICS:

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ASA

Acetaminophen

NSAIDs

± Adjuvants

1 Mild

A/Codeine

A/Hydrocodone

A/Oxycodone

A/Dihydrocodeine

Tramadol

± Adjuvants

2 Moderate

3 Severe

Morphine

Hydromorphone

Methadone

Levorphanol

Fentanyl

Oxycodone

± Adjuvants

• Don’t delay for investigations or disease treatment

• Unmanaged pain nervous system changesPermanent damageAmplification of pain

• Treat underlying cause (eg, radiation for a neoplasm)

PAIN MANAGEMENT BASICS

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• Conjugated in liver

• Excreted via kidney (90%–95%)

• First-order kinetics

• Time to Cmax

PO dosing ― 1 hourSC or IM dosing ― 30 minutes IV dosing ― 6 minutes

PAIN MANAGEMENT BASICS:OPIOID PHARMACOLOGY (1 of 2)

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• Steady state after 4–5 half-livesSteady state after 1 day (24 hours)

• Duration of effect of “immediate-release” formulations (except methadone)

3–5 hours PO or PRShorter with parenteral bolus

PAIN MANAGEMENT BASICS:OPIOID PHARMACOLOGY (2 of 2)

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Codeine, hydrocodone, morphine, hydromorphone, oxycodone

• Dose q4h

• Adjust dose daily

• Mild or moderate pain: ↑ 25%–50%

• Severe or uncontrolled pain: ↑ 50%–100%

• Adjust more quickly for severe uncontrolled pain

PAIN MANAGEMENT BASICSOral dosing of immediate-release preparations

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• Improve compliance, adherence

• Dose q8h, q12h, or q24h (product-specific)Don’t crush or chew tabletsMay flush time-release granules down feeding tubes

• Adjust dose q2–4 days (once steady state reached)

PAIN MANAGEMENT BASICSOral dosing of extended-release preparations

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• Use immediate-release opioids5%–15% of 24-h doseOffer after Cmax reached

• PO or PR: ~ q1h• SC or IM: ~ q30min• IV: ~ q10–15min

• Do not use extended-release opioids

PAIN MANAGEMENT BASICSBreakthrough pain

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• Ongoing assessment

• Increase analgesics until pain is relieved or adverse effects are unacceptable

• Be prepared for sudden changes in pain

• Driving is safe if pain is controlled, dose is stable, no adverse effects

PAIN MANAGEMENT BASICS

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If dose escalation adverse effects:

• Use more sophisticated therapy to counteract adverse effect

• Use an alternative: Route of administration Opioid (“opioid rotation”)

• Use a co-analgesic

• Use a nonpharmacologic approach

CONCERNS ABOUT OPIOID USE:POOR RESPONSE

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• Conjugated in liver

• 90%–95% excreted in urine

• If dehydration, renal failure, severe hepatic failure develops: dosing interval, dosage size

• If oliguria or anuria develops: Stop routine dosing of morphine Use only PRN

CONCERNS ABOUT OPIOID USE:CLEARANCE

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• Reduced effectiveness to a given dose over time

• Not clinically significant with chronic dosing

• If dose requirement is increasing, suspect disease progression

CONCERNS ABOUT OPIOID USE: TOLERANCE

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• Psychological dependence

• Compulsive use

• Loss of control over drugs

• Loss of interest in pleasurable activities

CONCERNS ABOUT OPIOID USE:ADDICTION

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• A process of neuroadaptation

• Abrupt withdrawal may abstinence syndrome

• If dose reduction required, reduce by 50%q2–3 days

Avoid antagonists

CONCERNS ABOUT OPIOID USE:PHYSICAL DEPENDENCE

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• Can have pain too

• Treat with compassion

• Protocols, contracting

• Consult with pain or addiction specialists

CONCERNS ABOUT OPIOID USE:SUBSTANCE ABUSERS

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• Meperidine — accumulates toxic metabolite normeperidine

• Mixed agonists/antagonists – Nubain, Talwin

• Do not use naloxone (Narcan) unless true respiratory crisis (RR < 6)

CONCERNS ABOUT OPIOID USE:THINGS TO AVOID

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• Ask the patient Palliative medicine corollary ― believe the patient

• Match the pain medicine to patient’s level of pain

• Increase pain medicine (with awareness ofCmax and half-life) until patient is comfortable

SUMMARY: BASIC PRINCIPLESOF PAIN MANAGEMENT

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• Very pleasant 68-year-old admitted with COPD exacerbation

• Home meds include 2 tablets of oxycodone5 mg/APAP “whenever my back acts up” — usually 4 tablets a day

• Appropriate pain medication order?

MRS PAINE

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• Readmitted months later with stage IV non-small cell lung cancer

• Taking 2 oxycodone/APAP tabs every 6 hours

• Rates her pain as 7/10 “most of the time”

MRS PAINE

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• Maximum acetaminophen dose in 24 hours is 4 grams Tylenol #3 (codeine 30 mg/APAP 325 mg) 24-hr maximum

= 12 tablets Percocet (oxycodone 5 mg/APAP 325 mg) 24-hr maximum =

12 tablets Tylox (oxycodone 5 mg/APAP 500 mg) 24-hr maximum

= 8 tablets Lortab 5 (hydrocodone 5 mg/APAP 500 mg) 24-hr maximum

= 8 tablets

• How long does it take to get a PRN dose of pain medication once it is requested?

KEY POINTS

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• Mrs Paine’s total daily oxycodone dose is40 mg (8 tablets 5 mg)

KEY POINTS

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