Pain Management Flashcards
Mechanisms of pain: nociceptive pain
Stimulation, transmission, perception, modulation
What is nociceptive pain caused by?
Injury to body tissues
Common descriptors of nociceptive pain
Aching, sharp, throbbing
Mechanisms of pain: neuropathic
Spontaneous transmission: nerves firing without stimulation
Common descriptors of neuropathic pain
Burning, tingling, hypersensitivity to touch or cold
Hyperalgesia definition
exaggerated pain
Allodynia definition
feeling pain from a stimuli that normally doesn’t cause pain
Acute pain causes
Trauma, surgery
Chronic musculoskeletal pain causes
Arthritis, OA, LBP, crystal-induced arthropathy
Chronic neuropathy pain causes
DM, post-herpetic, trigeminal, phantom
Chronic vascular pain causes
PVD, ulcers
Other cause of chronic pain
Cancer
Patient interview about pain: PQRSTU
Palliative/provocative
Quality
Radiation
Severity
Temporal
U (QoL)
Other ways to assess patient’s pain
Pain scales, pain diaries, ongoing function
Nonpharm management of pain
Physical activity: reverse deconditioning (increasing mobility to decrease pain)
Patient education for the caregiver/family
Cognitive-behavioral therapies for anxiety/depression
Adjuncts: heat, cold, massage, liniments, acupuncture, spirituality
Step 1 to managing pain (think of that step chart thing)
Nonopioid +/- adjuvant
Step 2 to managing pain
Opioid for mild-moderate pain +/- nonopioid +/- adjuvant
Step 3 to managing pain
Opioid for mod-severe pain +/- nonopioid +/- adjuvant
General principles for prescribing pain-control meds
Administer meds routinely, not PRN
Use least invasive route of administration first
Begin with a low dose, titrate carefully until comfort achieved
Reassess and adjust dose frequently to optimize pain relief while monitoring and managing ADEs
2016 CDC guidelines in prescribing opioids in patients with chronic pain: initiating or continuing opioids for CNCP
Recommend nonpharm and non-opioid treatments prior to opioids; if opioids are used, combine with non-opioids if possible
Establish treatment goals
Weigh risks vs. benefits
2016 CDC guidelines in prescribing opioids in patients with chronic pain: opioid selection, dosage, follow-up, D/C
IR formulations preferred initially, but can switch to XR for chronic pain
Administer the lowest effective dose and titrate slowly
Don’t prescribe them for any longer than necessary (≤3 days good)
Evaluate patients in 1-4 weeks, evaluate risks vs. benefits
2016 CDC guidelines in prescribing opioids in patients with chronic pain: assessing risk and harms of opioid use
Screen patients for risk factors for opioid-related harms before starting and periodically during therapy
Urine drug screens should be conducted when starting, then annually at minimum
Review controlled substance Rx Hx in PMP
Don’t use BZDs and opioids together
Provide resources for addiction help
Analgesic agents used for chronic pain
APAP, NSAIDs (COX-II), opioids
Pros of APAP
useful for mild-moderate pain, elder “safe,” adjunctive, “starting point” for initial and ongoing pharmacotherapy, no side effect profile
Cons of APAP
very few: hepatic failure, ethanol use, hepatic insufficiency, drug interaction with warfarin, MDD=4gm/day (be careful when using opioid/APAP combos), patient perception that it might not work because it’s an OTC, failure to complete an adequate trial
Pros of NSAIDs
useful for mild-moderate pain, musculoskeletal pain (inflammation, cancer)
Topical diclofenac (Voltaren) for “localized non-neuropathic persistent pain”, may be considered rarely, and with extreme caution, in highly selected individuals, other (safer) therapies have failed
Cons of NSAIDs
Ceiling effect: there is a maximum dose that will provide benefit; higher doses beyond that point won’t make it better or worse
NSAID CIs
Absolute CIs: PUD (ongoing PUD?), CKD, HF
Relative CIs: HTN, H. pylori infection, PUD history
Pros of opioids
moderate-severe pain, no ceiling dose (due to tolerance), routes for administration are diverse, long-acting agents available
Opioids vs. non-opioids for mod-severe chronic back pain, hip or knee OA pain
Non-opioids are preferred over opioids
Preferred opioids in the elderly
morphine, hydrocodone, oxycodone, hydromorphone, fentanyl
ADEs of opioids: pulmonary
respiratory depression, apnea
Diseases like asthma, COPD, sleep apnea may be CI’ed
ADEs of opioids: CNS
lethargy/sedation, pre-existing cognitive impairment, dysphoria, delirium, hallucinations
ADEs of opioids: ocular
mitosis (pinpoint pupils)
ADEs of opioids: GI
N/V, constipation
Management of N/V in opioid use
Haloperidol, droperidol
Chlorpromazine, prochlorperazine, thiethylperazine
Cyclizine, diphenhydramine, hydroxyzine, meclizine, promethazine
Hyoscine, scopolamine
Dolasetron, granisetron, ondansetron
Metoclopramide
Lorazepam
Management of constipation in opioid use
Docusate
Bisacodyl, casanthranol, senna
Glycerin suppositories, lactulose, mannitol, polyethylene glycol, sorbitol
Magnesium citrate, magnesium hydroxide, magnesium sulfate, sodium phosphates
Naloxegol, methylnaltrexone, nalmefene, naloxone
Mineral oil
Who qualifies for adjuvant therapy?
All patients with neuropathic pain
First-line adjuvant agents
Lyrica, gabapentin, SNRIs (duloxetine)
Caution with TCAs because they’re anticholinergic
Second-line adjuvant agents
Lidocaine, capsaicin
When to consider topical analgesics
If pain is focal or regional
Steroids as adjuvant therapy
Reserved only for patients with pain-associated inflammatory disorders or metastatic bone pain
Practice pointers for adjuvant therapies
Start low and go slow, monitor response, D/C ineffective drugs
Multipurpose adjuvant analgesics can be used for any type of chronic pain
Neuropathic pain: preferred approach is treatment with an AD analgesic or a gabapentinoid, and concurrent use of a topical agent if appropriate
Musculoskeletal pain disorders: addressed with multipurpose adjuvant analgesics like the ADs and tizanidine and topical agents
Minimizing risk of adjuvant analgesics
Consider if non-pharm care can be used and avoid using drugs
Consider if topical therapies can be tried and avoid systemic drugs
If a systemic drug may be useful, review the current drug regimen and consider deprescribing drugs with unclear benefit
Select a PO adjuvant analgesic for a trial based on type of pain, conventional practice, and risks associated with the potential for ADEs, including DDIs
If giving adjuvant therapy, make sure the prescribing information applies to the indication the drug has for pain
Modify conventional prescribing information to augment caution (start low and go slow, monitor!)
Have clear endpoints for evaluating effectiveness (pain relief, side effects, functional outcomes)
If the drug is ineffective, eliminate it, but be cognizant of the potential for discontinuation syndromes (ADs)
Educate the patient and caregivers that the use of these drugs is a trial-and-error process that requires time and careful monitoring
If you fail one adjuvant agent, is it predictive of failure of another?
No
Are adjuvant agents primary interventions?
No
