IPT Neuro: Pain Management Pharmacology and Cancer Pain Treatment + Cases

Somatic Pain:

1. Presentation

2. Treatments

1. Localized, sharp, throbbing- skin, bones, muscles

2. NSAIDs, opioids, APAP

Visceral Pain:

1. Presentation

2. Treatments

1. Deep, cramping, squeezing- internal organs

2. APAP, NSAIDs, Opioids

Neuropathic pain:

1. Presentation

2. Treatments to Use

3. Treatments to avoid

1. Burning, shooting, tingling, numbness

2. Treatments to use: anticonvulsants, TCA, topical lidocaine/capsaiacin

3. Treatments to avoid: NSAIDs, strong opioids

Some antibiotics and cancer treatments can worsen neuropathic pain

Pain Due to Muscle Tension:

1. Presentation

2. Treatments

1. Muscle soreness, pain when moving

2. Muscle relaxants

Inflammatory Pain:

1. Presentation

2. Treatments

3. Treatments to avoid

1. Localized warmth, swelling, redness

2. Treatments: NSAIDs

3. Treatments to avoid due to ineffectiveness- APAP

Describe the ascending pain pathway and what analgesics work on this pathway to reduce pain

Pain signals from body move up ascending pathway to spinal cord and to brain

Opioids block this pathway to block pain signals

Describe the descending pain pathway and what analgesics work on this pathway and how

Descending pathway goes from PAG, RVM, and VTA areas in hindbrain to spinal cord and then to body and sends signals to REDUCE pain

Opioids, TCAs, and SNRIs act on this pathway as it is mediated by serotonin and NE

Pain Assessment-PQRST

P=provoking factors

Q=quality

R= Region/Radiation

S= severity

T= Time

ARSs of APAP

Hepatotoxicity

DDIs of APAP

Hepatotoxic drugs

4 ADRs of NSAIDs

1. Hypersensitivity- respiratory distress and cuteanous symptoms

2. GI bleeding

3. Kidney injury

3. Increased risk of MI

NSAID DDIs

Nephrotoxicity drugs

Drugs that increase risk of GI bleed (steroids)

Drugs to avoid in pts taking muscle relaxants

Drugs that induce sleepiness or alcohol

What are the 2 antispasiticy drugs and MOA

Direct acting skeletal muscle relaxants- acts either on skeletal muscle or spinal cord

Baclofen

Tizanidine

What are the 4 antispasm drugs and their MOA

Centrally acting muscle relaxants-acts only on CNS

Cyclobenzaprine

Metaxalone

Methocarbamol

Carisoprodol

What drug acts as both an antiplasticity and antispasmodic drug

Diazepam

What are the 3 primary treatment of metastatic bone pain

1.Dexamethasone

2. IV Zolendronic acid

3. SC Denosumab

ADRs of early vs late treatment of opioids

Early- constipation, euphoria, respiratory depression, sedation

Late- myoclonus (muscle twitching), tolerance, constipation

For patients taking opioids, what would indicate them for treatment for constipation? What is the typical regimen?

All pts should be receiving laxatives while on opioids (unless they have diarrhea)

Typical regimen is combo of tow type of laxatives: stool softener + stimulant

Ex. Docusate + (senna or biscodyl)

Besides laxatives what drugs + MOA can be used for polio induced constipation

Mu receptor antagonists

Naloxegol

Naldemedine

Methylnaltrexone

Define opioid experienced patients

> 60 mg daily oral morphine equivalent doses for >1 week

Treatment of opioid naive patents:

Morphine IR: PO and IV

7.5-15mg PO q 4-6 hrs

2-5 mg IV q 3-4 hrs

Treatment of opioid naive patents:

Hydromorphone PO and IV dosing

2-4 mg PO q 4-6 hrs

0.5-mg IV q 3-4 hrs

Oxycodone dosing for opioid naive patients

5-10 mg PO q4-6 hrs

IV fentanyl dosing for opioid naive patients

12.5-50 mcg IV q 1 hr

IV: PO morphine ratio

1:3

IV to PO Hydromorphone ratio

IV Morphine to IV hydromorphine ratio

PO Morphine to PO Hydromorphone ratio

IV:PO Hydromorphone= 1:5

IV Morphine: IV Hydromorphone= 7:1

PO Morphine:PO Hydromorphone= 4:1

PO Morphine to IV fentanyl ratio

300:1

PO morphine to PO Oxycodone ratio

3:1

PO morphine to PO hydrocodone ratio

1:1

Fentanyl patch

1. How often applied

2. Onset of pan control + bridging

3. Steady state

Applied every 72 hours

Onset of pain control may take 12-72 hours (use short acting opioid initial 12-48 after application of first patch)

Steady state reached after 5-7 days

Baseline opioid dose (oral daily morphine equivalent dose)

-when to increase dose

-when to decrease dose, what specific side effects to look for

-when to reduce dose due to incomplete cross tolerance

Increase dose:

-if moderate pain increase by 25%-50%

-if severe pain increase 50% to 100%

PRN opioid dose

10%-20% of total daily scheduled opioid dose, and should be available q 4-6 outpatient and q 3-4 hrs inpatient

If switching from one opioid to fentanyl or methadone, how do you have adjust the dose due to cross tolerance

Continue at the same dose- fentanyl and methadone dont have cross tolerance

If switching from opioid to another opioid (not fentanyl or methadone) how do you have to adjust the dose due to cross tolerance

Reduce dose by 50% due to cross tolerance