pain management & opioid analgesics. objectives determine proper opioid dosing determine proper...
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Pain Management & Opioid Analgesics
ObjectivesDetermine proper opioid dosingDifferentiate between specific opioid analgesics and be able to convert between agentsDiscuss basal and bolus doses for PCADiscuss adverse reactions of opioidsReview the Sole Provider programDiscuss how to properly write a prescription for a controlled substance*
PainDefinitionAn unpleasant sensory & emotional experience associated with actual or potential tissue damage or described in terms of such damageTypesNociceptiveSomatic bone pain, skin, soft tissue traumaVisceral ab pain due to tumor invasionNeuropathic post herpetic neuralgia, post-mastectomy, phantom limb*
Choosing Analgesic TherapyWhat type of pain?Nociceptive vs. neuropathicAcute vs. chronicMild vs. severeWhat route should be used?What agent should be used?Type, severity of painPt characteristics side effects, elderly, allergy, co-morbid conditions, tolerance, previous narcotics usedInsurance, cost*
WHO Ladder of Analgesicswww.anzsgm.org/vgmtp/Pain/analgesia_ladder.htm
Non-opioid analgesicsAspirinNSAIDsAcetaminophenAdjuvantsAntidepressants amitriptyline, duloxetineAnticonvulsants carbamazepine, gabapentin, pregabalinAnesthetics lidocaine patch (12 hours on, 12 hours off)*
Potency of OpioidsWeak AgonistsPropoxyphene (Darvon, Darvocet)CodeineHydrocodone/APAP (Vicodin, Lortab, Lorcet, Norco)TramadolStrong AgonistsMorphineOxycodoneHydromorphone (Dilaudid)Fentanyl (Duragesic, Sublimaze)Methadone (Dolophine)Meperidine (Demerol)*
- TramadolSynthetic analog of codeine but is NOT controlledWeak agonist/low affinity at mu receptor and also weak SNRI (which inhibits pain transmission in the spinal cord) Use with caution in pt on TCAs, MAOIs, SSRIs as it may lower seizure thresholdMax dose is 400 mg/day but 300 mg/day if >75yo; renal dosing if CrCl
Considerations in choosing opioidsRenal impairmentPreferred oral agent: hydromorphoneUse with caution: morphine, codeineAvoid meperidineMetabolites can accumulate and cause seizuresOther cautions with meperidineAvoid in pts with CHF, hepatic insufficiency, elderlyAvoid use in pts on MAOIs (phenelzine, selegeline, linezolid) in past 14 days*
OpioidHalf-lifeOnsetDuration of analgesic effectFentanylIV: 2 4hPatch: 17h IV: within minutesPatch: 12-24h IV: 0.5 1hPatch: 72hHydromorphone (Dilaudid)2 3hIV: 5 - 15 minPO: 30 min3 5h Methadone**8 59h30 60 min4 8h Morphine2 4h IV:5 - 10 minPO (IR): 30 - 60 minIR: 3 6h SR: 8 12hMeperidine (Demerol)3 - 5h (15-30h for metabolite)10 45 min2 4hCodeine3 4h30 60 min4 6hOxycodoneIR: 2 5h SR: 5h 15 60 minIR: 3 6hSR: 12hHydrocodone3 4h10 60 min4 8h
OpioidUsual Starting DoseCommentsFentanyl*25 100 mcg IV q1h, then 1 2 mcg/kg/hPatch: NOT for acute pain & NOT for opioid-nave pts; do not cut patch in halfHydromorphone (Dilaudid)0.5 1 mg q4h IV1 2 mg q4h POVery potent; preferred in pts with renal impairmentMethadone5 mg q8-12h POMonitor for QT prolongation & drug interactionsMorphine2 5 mg q4h IV5 10 mg q4h PO (IR)15 30 mg q8 or 12h (SR)MSContin: NOT for acute pain; do not split/crush tabletsMeperidine (Demerol)50 mg q3-4h PO/IVNOT recommended for chronic useCodeine30 60 mg q4h POHas more side effects than morphineOxycodone5 mg q4h PO (IR)10 20 mg q12h (SR)OxyContin: NOT for acute pain; do not split/crush tabletsHydrocodone5 10 mg q4h POalways combined with APAP or ibuprofen which limits its dosing
OpioidAvailable DosesFentanylIV: 25, 50, 100 mcg/mlPatch: 25, 50, 75, 100 mcgHydromorphone (Dilaudid)IV: 2 mg/ml; PCA: 1mg/ml & 0.2 mg/mlPO: 2 mgMethadonePO: 5, 10 mgMorphineIV: 4 mg/ml; PCA: 1 mg/ml & 5 mg/mlPO: IR 15, 30 mgPO: ER (MS Contin): 15, 30, 60, 100 mgSolution (Roxanol): 20 & 2 mg/mlMeperidine (Demerol)IV: 25, 50, 100 mg/mlCodeinePO: 30 mgOxycodonePO: IR 5mgPO: ER (OxyContin): 10, 20, 40, 80 mgSolution (Roxicodone): 20 & 1 mg/mlOxycodone/APAP (Percocet)PO: 5mg oxycodone/325 mg APAPHydrocodone/APAP (Norco)PO: 5mg hydrocodone/325 mg APAP
PCA DosingDosing considerationsFor opioid-nave patients, use lower end of rangePain AssessmentRespiratory AssessmentSedation Assessment
*When initiating PCA for first time (no conversion from outpatient med), the initial demand dose is 50% of the basal rate
Drug (standard concentrations)Usual DemandDoseRange of Demand Dose Lockout Interval (min)Usual Basal RateMorphine (1mg/ml and 5 mg/ml)1.0 mg0.5-2.5 mg5 - 15None or1 2 mg/hrHydromorphone (Dilaudid)(0.1 mg/ml and 1 mg/ml)0.2 mg0.05-0.4 mg5 - 15None or0.1 0.4 mg/hr
PCA dosing62 yo patient s/p TAH has been moved to PACU. You have been asked to start the patient on a PCA. Which of the following is an appropriate order:Morphine PCA 1 mg/ml: LD 2 mg, 1 mg demand dose, lock out 10 min, no basalDilaudid PCA 1mg/ml: LD 2 mg, 1 mg demand dose, lock out 10 min, no basalFentanyl patch 25 mcg q72 hours*initial
Conversions**When switching between opioids, there is NOT a complete cross tolerance. If patient is controlled, consider decrease the dose by 1/2 to 1/3 to avoid side effects.
**conversion ratio is highly variable
*Decreasing IV potency as you go down the table
OpioidParenteralOralFentanyl0.1 mgNAHydromorphone (Dilaudid)1.5 mg7.5 mgMethadone**5 - 10 mg2 - 20 mg***Morphine10 mg30 mgMeperidine (Demerol)75 -100 mg 300 mgCodeine120 mg200 mgOxycodoneNA20 mgHydrocodoneNA30 mg
For CHRONIC pain: 25 mcg/hr fentanyl patch = oral morphine 50 mg/24h
Initial Fentanyl Patch Dose ConversionPO 24-hour morphine (mg/day)Fentanyl Patch Dose (mcg/hr)45-13425135-22450225-31475315-404100405-494125495-584150585-674175675-764200765-854225855-944250945-10342751035-1124300
Fentanyl patchNOT for acute pain or post-op painAbsorbed through the skin, producing a drug depot in the upper skin layers, then diffusing into systemic circulationCan have variable responses between patients (i.e. cachetic, elderly)Watch for drugs that inhibit its metabolismKetoconazole, erythromycin, diltiazem, grapefruit juice
Oral morphine-equivalent daily dose (mg/day)Initial Dose Ratio(oral morphine:oral methadone)100020:1 or greater
Breakthrough DosingUse immediate-release opioidsChronic oral medsGive 10 20% of the total daily dose q4hprnExample MS Contin 60 mg PO q12h should give 10 20 mg q4h prn of morphine immediate releaseIV dosing (PCA dosing)10% of the 24 hr requirement, then:Divide by 4 if giving every 15 minutesEx: 100 mg morphine daily 2.5 mg IV q15 min*
Dose AdjustmentIncreasing the opioid dosage For moderate to severe pain, increase by 50 100%For mild to moderate pain, increase by 25 50%Convert to oral as early as possible: Pain is controlledGI function intactIV to oral dosage calculationCalculate total daily IV useCalculate breakthrough dose10-20% of total daily dose of regularly scheduled opioid every 4 h as needed
Conversion problemPt is taking Percocet 5/325 two tabs q6h
What dose of oxycodone ER (OxyContin) would you start the patient?
What dose of morphine ER (MS Contin)?
What dose of fentanyl patch?*
Conversion problem8 tabs Percocet = 40 mg oxycodone per day
Oxycodone ER (OxyContin) = 20mg q12h
Conversion ProblemMS Contin conversion40 mg po oxycodone = 20 mg po oxycodone x 30 mg po morphineX = 60 mg po morphine daily = MS Contin 30 mg q12hIf you want to decrease dose to allow for decreased cross-tolerance, decrease dose by 1/2 to 1/3 = 30 to 40 mg morphine daily = MS Contin 15 mg q12hFentanyl patch30 60 mg po morphine daily = 25 mcg fentanyl patch
Conversion problemIn the previous problem, your patient was stable on MS Contin 30 mg q12hYour attending wants to change over to the fentanyl patchHow do you time the transition from MS Contin to the patch?*
Conversion problemIn the previous problem, your patient was stable on MS Contin 30 mg q12hYour attending wants to change over to the fentanyl patchHow do you time the transition from MS Contin to the patch?It takes about 12 hrs for onset of fentanyl patchGive patient one last dose of MS Contin at the same time the patch is applied*
Example of conversion from oral med to PCAPt taking OxyIR 20 mg PO q4h Pts pain is well-controlledWant to convert to hydromorphone PCAWhat would be a basal dose (in mg/hr)?
What would be the bolus/demand dose?*
Example of conversion of oral med to PCAPt taking OxyIR 20 mg q4hConvert total oral daily dose (120 mg oxycodone) to oral hydromorphone 120 mg po oxycodone = 20 mg po oxycodone x7.5 mg po hydromorphoneX = 45 mg po hydromorphoneConvert to IV45 mg po hydromorphone =7.5 mg pox1.5 mg IVx = 9 mg IV hydromorphone daily*
Example of conversion to PCABasal rate9 mg daily total = 0.4 mg per hourMay want to decrease basal by 1/2 to 1/3 to account for incomplete cross toleranceBasal dose of 0.2 to 0.3 mg per hourBolus/demand dose is usually 10% of the daily dose divided by 4(0.10 x 9 mg) / 4 = 0.2 mg q 15 minutesTitrate based on use & pts response
Example of PCA conversion to oral medPt on post-op morphine PCA with basal of 1 mg/hr and bolus of 1 mg q15 minutesPt used 40 bolus injections in 24 hoursWhat dose of oral morphine (basal & breakthrough) should be used?
What dose of oral oxycodone (basal & breakthrough) should be used?*
Example of PCA conversion to oral medTotal daily use of IV morphine1 mg/h x 24 h + 40 bolus = 64 mg/24 hourConvert to oral morphine64 mg IV morphine = 1 mg IV morphinex3 mg po morphineX = 192 mg po morphine MS Contin 100 mg q12h (basa