IC6 opioids, pain Flashcards
pain ladder
- Pain ladder for pain assessment and management based on pain severity
- Individualised therapeutic planning required
MILD 1-3: non-opid +/- adjuvant
MOD 4-7: opioid for mil-mod +/- non opioid +/- adjuvant
SEVERE ≥8: opioid for mod-severe pain +/- non opioid +/- adjuvant
general principles for pain management
- select most app med based on pain diagnosis, comorbid, potential DDI
- analgesic regimen: opioid, nsaid, paracetamol, adjuvant
- treat analgesic AE (OIC)
- psychosocial support
- provide pt and fam/ caregiver education
- optimise integrative interventions
Initiation of opioids should start with
titration of short-acting opioids as needed, lowest effective dose for shortest duration needed.
* short acting: rapid analgesic effect
* ROA: depends on pt analgesic needs
* (optimise nonopioid therapies while on opioid.
starting dose
The lowest starting dose for opioid-naïve patients is often equivalent to a single dose of approximately 5–10 MME
Max daily dosage of 20–30 MME/day. (morphine mg equivalent)
pt with chronic persistent pain
stable doses of short-acting opioids should be provided with (ER) or (LA) opioids + “rescue dose” to manage breakthrough or transient exacerbations of pain.
- The rescue dose is usually equivalent to 10%–20% of the total opioid daily consumption
- may be given every hour PRN severe exacerbations of pain.
- Rapid onset and short duration are preferred as rescue doses.
The repeated need for numerous rescue doses per day may indicate the need to adjust baseline treatment
initiation of ER/LA opioids
- received certain dosages of immediate-release opioids daily (e.g., 60 mg daily of oral morphine)
- additional caution with ER/LA opioids and consider a longer dosing interval when prescribing to patients with renal or hepatic dysfunction
* interindividual PK variability and organ function = decreased CL --> accumulation of drugs to toxic levels * reducedose by 25-50% due to incomplete cross-tolerance, risk of overdose
management of psychosocial support and education
educate on Diversion, misuse of opioids and addictive potential
management on constipation
- Constipation routinely evaluated and managed
□ Prophylactic - pharmacologic therapy (e.g., a stimulant laxative such as senna, with or without a stool softener) for regular bowel movements if opioids are used for more than a few days.
□ Stool softeners or fiber laxatives without another laxative should be avoided.
management of withdrawal
- discuss an opioid tapering plan when opioids will be used around the clock for more than a few days.
□ Limiting opioid use to the minimum needed to manage pain (e.g., taking the opioid PRN if needed less frequently than Q4H
□ help limit development of tolerance and therefore withdrawal after opioids are discontinued.
Non-opioid analgesics
- Paracetamol (possible hepatotoxicity, renal impairment)
□ Combi with opioid (hydrocodone, codeine), caution due to liver injury (max 4g/d) - NSAIDs
□ Prophy w/ PPI, misoprostol
□ Use as combi to reduce opioid dose (sedative, cognitive function effects)
□ TOPICAL can be used - Adjuvant — gabapentin, pregabalin, SSRI, SNRI, TCA, Corticosteroids, local anaesthetics (lidocaine)
MOA of adjuvants (antidep, anticonvulsants, CS)
to enhance opioid analgesia and treat neuropathic component of pain, reduce dose of opioids (less AE)
- Antidep: Risk of SS, qtc prolongation, potential CYP2D6 inhibition (fluoxetine, fluvoxamine, bupropion, duloxetine)
- Anticonvulsant: gabapentin
- Corticosteroids: tx bone pain and neuropathic pain syndrome + anti-inflamm effects
non-pharm for pain management
stress reduction, CBT, biofeedback. Walking supports, massage, heat. Ice, TENS (transcutaneous electrical nerve stimulation), acupuncture
morphine PK
Morphine is metabolized in the liver glucuronidation by uridine 5′-diphospho-glucuronosyltransferase (UGT) phase II enzymes.
to morphine-6-glucuronide and morphine-3-glucuronide
- M3G: no effect. M6G: greater analgesia potency and toxicity effect
- both of which are excreted by the kidneys.
morphine DF
morphine SYRUP is not a controlled drug in sg
- 5 to 15 mg of oral short-acting morphine sulfate or equivalent for opioid-naıve patients
- IV is 1/3 of PO dose (2-5mg) for naive
- 60mg/d means tolerant
monitoring of opioids use
- Pain relief
- respiratory and mental status/alertness (especially in patients on concomitant CNS depressants, including benzodiazepines)
- BP, heart rate
- signs of misuse, abuse, or substance use disorder
- symptoms of serotonin syndrome such as mental status changes (eg, agitation, hallucinations, coma), autonomic instability (eg, tachycardia, labile BP, hyperthermia), neuromuscular changes (eg, hyperreflexia, incoordination)
- GI symptoms
morphine –> tramadol
30mg PO morphine –> 300mg PO tramadol
tramadol MOA and Dose
weak opioid, mu opioid receptor binding and monoamine (serotonin and norepinephrine) reuptake blockade (mixed mechanism).
100mg TDS
Tab 200mg, 100/ 150mg PR, 50mg
37.5mg (w/ 200mg paracetamol)
Suppository
50mg/ml inj
tramadol DDI
CNS Depressants: Alcohol, other opioids, CBZ (X), Phenobarbital (D), Primidone (D), TCAs (D)
Serotonergic risk: MAOis (e.g. Isocarboxazid, Phenelzine, Moclobemide, Selegiline; X), Linezolid (D)
2D6i: strong: Fluoxetine, sertraline
Paroxetine, Duloxetine, Bupropion, Quinidine, ritonavir, terbinafine.
3A4 inhibitors: Fexinidazole (X), Fusidic Acid (X)
cyp2d6 PK
codeine, hydrocodone, methadone, oxycodone, tramadol
need CY2D6 to convert to active metabolite for analgesic effect
- PM: low efficacy
- URM: toxic
dose conversion table considerations
May reduce 25-50%, due to incomplete cross-tolerance, prevent overdose.
- How long have they been on the meds (tolerance)
- Is pain well-managed?
- Kidney/ liver impairment? (liver metabolism for opiates)
- Age of pt, comorbidities, frailty
- titrate to patient-specific treatment goals (eg, improvement in function and quality of life, decrease in pain using a validated pain rating scale)
short acting –> long acting pain
- add 50 - 100% of PRN into long acting (basal + PRN)
- Rescue dose is usually equivalent to 10%–20% of the total opioid daily consumption
morphine to fentanyl
2 - 3.6mg PO morphine = 1mcg/hr fentanyl patch
when to use fentanyl patch
- Opioid tolerant (using 60mg morphine/d or equiv)
- unable to tolerate other DF
strengths of fentanyl patchs and PK
(12, 25, 50, 75, 100 mcg/hr) TD patch
Nasal spray
IV (for ICU)
t1/2 (20-27hrs for patch), highly lipophilic, stay in subcutaneous fats, muscle = depot
- Max duration 72hrs, may change every 24-48hr if wearing off
counsel for fentanyl
- Make sure there is someone with you, monitor resp depression, may be in overdose
- Not on broken skin, rashes
- Do not apply heat, exercise
methadone MOA
synthetic opioid analgesic with full agonist activity at the µ-opioid receptor
and have N-methyl-D-aspartate (NMDA) receptor antagonism
(dampens a major excitatory pain pathway)
- analgesic effect, less tolerance effect
methadone pK
Long t1/2: 15 - 120hrs (steady state reached days~2wks)
- Metabolized by hepatic pathways
- observe for drug accumulation and adverse effects, especially over first 4–5 days. In some individuals, steady state may not be reached for several days to 2
weeks.
methadone indication
- detox, heroin dependence
- opioid dependence, pain not well controlled
- help pt save $, reverse tolerance
Monitor over first 4-7days
Due to its long half-life, high potency, and interindividual variations in PK, methadone, when indicated, should be started by or in consultation with an experienced pain or palliative care specialist
morphine conversion to methadone
<60mg: 2-7.5mg metahdone/d
60-199mg: 10:1 (& pt <65yrs)
≥200mg: 20:1 (& pt >65yrs)
ketamine MOA
Non-competitive NMDA receptor antagonist that blocks glutamate.
Enhances descending inhibiting serotoninergic pathways and can exert antidepressive effects.
Low doses produce analgesia, and modulate central sensitization, hyperalgesia and opioid tolerance
ketamine indication
+consideration when initiate
- Pts with opioid HYPERALGESIA (incr sensitivity to pain)
- Reverse opioid tolerance, REDUCE baseline opioid >50% when initiating ketamine, MONITOR
ketamine dose and AE
Initial: 0.5 mg/kg/day administered in 3 to 4 divided doses
(max 800mg/d)
50mg/ml inj –> given as PO sol in NUH + flavouring
AE: agitation, confusion, delirium, dreamlike state, excitement, hallucinations, irrational behavior, vivid imagery
CDC guideline using opioid
- prescribe no greater qty than needed
- evaluate benfits and risks early and regularly
- monitor opioid-related harms and mitigation steps
- drug monitoring program, NEHR, drug urine test
- caution with BZP + opioid + CNS depressants
- tx OUD with meds, do not stop abruptly, taper!
tapering
- when risk > benefits, optimise nonopioid therapies and taper
- longer duration ≥1yr: taper 10% per mnth, will be better tolerated
Other medications addressing specific symptoms (NSAIDs, acetaminophen, or topical menthol or methyl salicylate for muscle aches;
trazodone for sleep disturbance;
prochlorperazine, promethazine, or ondansetron for nausea;
dicyclomine for abdominal cramping;
and loperamide or bismuth subsalicylate for diarrhea)
duration of opioid therapy
shortest duration possible:
- common causes of nontraumatic, nonsurgical pain, when opioids are needed, a few days (4-7d) or less are often sufficient
- evaluate every 2wks if opioids need to continue for acute pain
- evaluate every 1-4wks for benefit of opioids in subacute or achronic pain
- evaluate risk of OPIOID USE DISORDER : dose ≥ 50MME, pt risk factors
opioid tolerance
reduced response to medication, require more opioids for same effect
MME for tolerance and eg
25 mcg/h fentanyl patch,
60mg of morphine daily
30 mg of PO oxycodone daily,
8 mg of PO hydromorphone daily
or an equianalgesic dose of another opioid for a week or longer
opioid dependence
body adjust its normal function around regular opioid use. Unpleasant physical sx occur when stopped
opioid addiction
(OPIOID USE DISORDER) when attempts to cut down or control use are unsuccessful, result in social problems (work, school home)
* Comes after tolerance and dependence, making it physically challenging to stop opioid use and incr risk of withdrawal
* withdrawal effects: drug craving, anxiety, restlessness, gastrointestinal distress, sweat, and tachycardia, flu-like sx
opioid use disorder pt risk factors
- Hx of prescription, illicit drug, alcohol dependence/ sub abuse
- Pt with hx of binge drinking/ peers
- Fam hx of sub abuse
- Hx of psychiatric disorder (ANX, DEP, ADHD, PTSD, bipolar, schizophrenia)
- Hx of sexual abuse victimisation
- Young age <45yrs
- Hx of legal prob, incarceration
- Med assisted tx for sub use disorder
palliative care
make sx better, improve QOL
- for any stage
- may not require med
supportive/ comfort care
make pt FEEL better
- withdraw therapeutic if harm > any benefits
EOL syndromes
pain
dyspnea
secretion
agitation, delirium
bowel obstruction
others: anorexia, cachexia, N,C,D, insomnia, sedation, wound care/ pressure ulcers
dyspnea management
(>12-25 RR at rest)
- non-pharm considered.
- Morphine PRN, titrated to respiratory rate <20breath per min (slow breathing)
- Fluid overload: furosemide PRN
- Anxiety, dying pt: lorazepam 0.25mg-1mg PO every 2-4h PRN
secretions management
- Glycopyrrolate (exempt in SG) 0.2-0.4mg IV/SC every 4h PRN
- other Anticholinergics can be given, weigh toxicities and pt preference
* Scopolamine PRN 1.5mg patch (1-2 patch every 72h)
* Atropine/ hyoscyamine 0.125-0.25mg PO Q4H
agitation/ delirium management
- remove contributing factors to delirium, I WATCH DEATH – consider deprescribing
- supportive care (pain, electrolyte, nutritional)
- Antipsychotics as last resort (quetiapine > olan > halo) > lorazepam (alc/ BZP withdrawal)
Anorexia, cachexia management
- Gastroparesis: Metoclopramide 5-10mg PO QDS 30mins before meal
- Low appetite: Megestrol acetate
1) Olanzapine 2.5-5mg PO
2) Dexamethasone 3-8mg/d
OIC prophylaxis considered for
considered for prophylactic laxative therapy when opioid treatment is initiated:
advanced age
immobility
poor diet
intra-abdominal pathology neuropathy
hypercalcemia
concurrent use of other constipating drugs
