Lecture 76 - Non-Malignant Pain Part 2

Question 1

Gabapentinoids: Gabapentin (Neurontin) and Pregabalin

Answer 1

Uses: Fibromyalgia; Neuropathies; Post-operative pain
Available formulations: Tablets/capsule; ER tablet; Liquid solution
Recommended dosing: Gabapentin (Neurontin): 100-300mg PO TID (max 3600mg/day); Pregabalin (Lyrica): 75mg PO BID (max 600mg/day)
Side effects: Sedation, dizziness, peripheral edema
Clinical pearls: Renally dose adjusted; Titrate up dose to limit sedation; Use in combination to ̄ requirements of other analgesics; Pregabalin is a schedule V controlled substance, gabapentin is unscheduled

Question 2

SNRI’s: Venlafaxine (Effexor) Duloxetine (Cymbalta)

Answer 2

Uses: Fibromyalgia; Neuropathy
Available formulations: Capsule/tablet; ER capsule/ER tablet
Recommended dosing: Venlafaxine: 37.5 – 75mg PO daily (max 225mg/day); Duloxetine: 30mg PO daily x 1 week, then increase to 60mg PO daily (max 60mg/day)
Side effects: Nausea, headache, hypertension, sedation, weakness
Clinical pearls: Start low dose and titrate up to minimize side effects; Renally dose adjust venlafaxine and avoid duloxetine for CrCl < 30 mL/min

Question 3

TCA’s: Amitriptyline (Elavil)* Nortriptyline (Pamelor)

Answer 3

Uses (all off label): Fibromyalgia; Neuropathy; Migraine prophylaxis
Available formulations: Tablet (amitriptyline); Capsule (nortriptyline); Oral solution (nortriptyline)
Recommended dosing: Amitriptyline or nortriptyline: 10mg PO QHS (max
150mg/day)
Side effects: Anti-cholinergic side effects, sedation
Clinical pearls: Last line option for neuropathy and fibromyalgia due to side effects

Question 4

Muscle Relaxants: Cyclobenzaprine (Amrix, Fexmid) Baclofen (Lioresal) Methocarbamol (Robaxin) Carisoprodol (Soma) Tizanidine (Zanaflex)

Answer 4

Uses: Musculo-skeletal pain/spasms
Available formulations: Tablet/capsule (IR/XR); Oral suspension (baclofen); Parenteral solution (methocarbamol, baclofen)
Recommended dosing: Cyclobenzaprine 5 mg PO TID (max 30mg/day); Baclofen 5mg PO TID (max 80mg/day); Carisoprodol 250-350 mg PO TID (max 1050mg/day); Methocarbamol 1.5 g PO 3-4x/day (max 8g/day); Tizanidine 2-4 mg PO q8-12h (max 24mg/day)
Side effects: Sedation/ drowsiness, dizziness, dry mouth, vision changes
Clinical pearls: Short term use (<3 weeks); Carisoprodol is schedule IV due to abuse potential

Question 5

Antiepileptics: Carbamazepine (Tegretol)

Answer 5

Uses: Neuropathic pain
Available formulations: Tablet; ER capsule/tablet; Chewable tablet; Suspension
Recommended dosing: 200mg-400mg PO daily in 2-4 divided doses (max
1200mg/day)
Clinical pearls: Increased risk of hypersensitivity reaction in patient with HLA-B*1502 allele; Autoinduction of hepatic enzymes (levels will fall over first few weeks of use)

Question 6

Topical Agents: Lidocaine

Answer 6

Available formulations: Patch (4% OTC, 5%); Injection; Topical (cream, gel, ointment, lotion, spray, liquid)
Recommended dosing: Apply 1 patch to affected area daily and remove 12 hours later (can vary by manufacturer)
Side effects: Hypotension, arrythmia (minimal risk with patch)
Clinical pearls: Tachyphylaxis with continuous use; 12 hour break between patches; Local effect- apply to site of pain

Question 7

Topical Agents: Capsacian

Answer 7

Uses: Muscle/joint pain; Neuropathic pain
Available formulations: Cream, gel, liquid, lotion: Apply 3-4 times per day; Patch: Apply 1 patch to affected area daily and remove 8 hour later u Side effects: Skin irritation and pain
Clinical pearls: Do not get medicine into eyes (burning); Wash hands after applying; Some formulations available OTC

Question 8

Non-COX-2-selective NSAIDs, oral *includes aspirin >325mg/day in older adutls

Answer 8

Increased risk of GI bleeding or peptic ulcer disease in high-risk groups
Avoid chronic use unless other alternatives are not effective and the patient can take a gastroprotective agent (proton- pump inhibitor or misoprostol

Question 9

Indomethacin, Ketorolac (oral and parenteral) in older adults

Answer 9

Increased risk of GI bleeding/peptic ulcer disease and acute kidney injury in older adults
Of all the NSAIDS, indomethacin has the most adverse effects, including a higher risk of CNS effects
Avoid

Question 10

Skeletal muscle relaxants: Carisoprodol, Cyclobenzaprine, Methocarbamol in older adults

Answer 10

Poorly tolerated by older adults because some have anticholinergic adverse effects, sedation, and increased risk of fractures
Avoid

Question 11

SNRIs, TCAs, Carbamazepine in older adults

Answer 11

May exacerbate or cause SIADH or hyponatremia; monitor Na levels
use with caution

Question 12

Opioids and benzodiazepines in older adults

Answer 12

Increased risk of overdose and adverse events
Avoid

Question 13

Opioids and gabapentin/pregabalin in older adults

Answer 13

Increased risk of severe sedation- related adverse events in older adults including respiratory depression and death
Avoid
Exceptions
* Transitioning from opioid to
gabapentinoid
* Using gabapentinoid to reduce
opioid dose

Question 14

Anticholinergic in older adults

Answer 14

Increased risk of cognitive decline, delirium, and falls or fractures.
Avoid

Question 15

Antiepileptics (including gabapentinoids)
Antidepressants (TCAs, SSRIs, and SNRIs)
Antipsychotics Benzodiazepines
Z drugs
Opioids
Skeletal Muscle Relaxants
in order adults

Answer 15

Increased risk of falls and fracture with concurrent use of three or more CNS-active agents
Avoid concurrent use of three or more CNS-active drugs

Question 16

Opioid Antagonist

Answer 16

naloxone

Question 17

Opioid weak agonist

Answer 17

codeine
tramadol

Question 18

Opioid full agonist

Answer 18

• Morphine
• Hydrocodone
• Hydromorphone
• Oxycodone
• Meperidine
• Fentanyl
• Methadone

Question 19

Tolerance

Answer 19

Medication becomes less effective over time and it takes a higher dose of the drug to achieve the same effect

Question 20

Dependence

Answer 20

When a patient stops using a drug, their body goes through withdrawal

Question 21

Addiction

Answer 21

Continued use of a drug despite negative consequences

Question 22

Signs and Symptoms of Opioid Overdose

Answer 22

• Sedation/decreased level of consciousness (LOC)
• Pinpoint pupils
• Decreased respiratory rate
• Bradycardia
• Hypotension
• Pale, clammy skin

Question 23

Signs and Symptoms of Opioid Withdrawal

Answer 23

• Insomnia/Agitation
• Dilated pupils
• Increased respiratory rate
• Tachycardia
• Hypertension
• Sweating

Question 24

Treatment of opioid overdose

Answer 24

Naloxone (Narcan): Opioid Antagonist
Available in different formulations: Intravenous (hospital) u 0.4-2mg IV q2-3min; Nasal spray (community); 4mg intranasal spray q2-3min (alternate nostrils)
Can precipitate opioid withdrawal
Prescribe together with opioids in patients at risk for overdose

Question 25

Naloxone (Narcan)

Answer 25

Who should receive co-prescription of naloxone?
Considering prescribing naloxone for patients at risk of overdose, such as ANY of the following: History of overdose; History of substance use disorder; Higher opioid dosages (≥50 morphine milligram equivalents (MME)/day); Concurrent benzodiazepine use

Question 26

Opioid Withdrawal

Answer 26

Onset: Short-acting opioids (e.g. heroin): 8-24
hours after last use; duration 4-10 days; Long-acting opioids (e.g. methadone): 12-48 hours after last use; duration 10- 20 days
Treatment: Clonidine - Helps with symptoms of withdrawal such as HTN, sweating, vomiting and anxiety; Buprenorphine; Methadone