pharmacy intro
DESCRIPTION
Pharmacy Intro. Opioids and other drugs we use on palliative care. Objectives. Discuss the role of opioids in end of life care Discuss the pharmacology and side effects of opioids Discuss opioid equivalencies and conversions Review basics of methadone Discuss other medications commonly used. - PowerPoint PPT PresentationTRANSCRIPT
Pharmacy IntroOpioids and other drugs we use on palliative
care
Objectives
Discuss the role of opioids in end of life careDiscuss the pharmacology and side effects of opioidsDiscuss opioid equivalencies and conversionsReview basics of methadoneDiscuss other medications commonly used
Objectives (cont’d)
Discuss other medications commonly used
Barriers to opioid use
Physician Patient
Why use opioids
Pain is experienced by over 80% of patientsOver 60% will be moderate to severe
Dyspnea present in 80% of advanced cancer95% COPD at end of life75% of advanced disease (all comers)
Opioids in Canada
Opioid Pharmacokinetics
All have similar PK (except methadone)onset of action 15-30 minsduration of action 4-5 hrs
LA 8-12hrs
Opioid Pharmacokinetics
Fentanyl and SufentanilOnset 10-15 minsDuration 45 minsFirst pass metabolismHighly lipophilic (SL/IN)
Opioid Dosing
No ceiling effect↑dose = ↑analgesic effect (log-linear)Dose increased until symptom relief or limiting side effects
Start with IR dosing
“Start Low and Go Slow”
Q4H
PO = SL = PR
SC/IV = 50% of PO
Reassess regularly
Breakthrough DoseIR50-100% of the Q4H dose or 10% of the 24hr doseQ1H - PO/SLQ30Min - SCQ10Min - IVFor simplicity... all routes are Q1H prn
Do Not Use Extended Release Opioid for Breakthrough
Titration
Increase equal to total 24 hours breakthrough doseMild to moderate pain - 50%If no response
Increase more rapidlySwitch to parenteral
Opioid Rotation
Why?Inadequate analgesia despite appropriate escalationIntractable/Intolerable side effectsAltered renal/hepatic functionDrug shortages
Use a consistent method
Use the same conversion table
Consider incomplete cross-tolerance, patient variations, limitation of tables
Equianalgesia Dose Ratio
Equianalgesia refers to different doses of two agents that provide approximate pain reliefDoes not reflect interpatient variabilityRatio differs in acute and chronic useDoes not use incomplete cross tolerance
Opioid Equivalency Morphine: Drug
Oral (mg) 2:1 Parenteral (mg)
Morphine 10 5Codeine 1:10 100 --Tramadol 1:5 50 --Oxycodone 2:1 5 --Hydromorphone 5:1 2 1Fentanyl 100:1 -- 50 (mcg)Sufentanil 1000:1 -- 5 (mcg)Methadone 10:1 1 --
Fentanyl
Morphine BT (mg po) 10 20 30 40 50 80 160
Morphine 24H (mg po) 100 200 300 400 500 800 1600
Fentanyl Transdermal (mcg/h) 25 50 75 100 125 200 300
Hydromorphone 24H (mg po) 20 40 60 80 100 160 240Hydromorphone BT (mg po) 2 4 6 8 10 16 24
Fentanyl Patch
For relatively stable painPermeates the skin and a depot is formed12hrs to develop analgesiaPlasma levels stabilize after 2 sequential patch applicationsHalf-life about 17 hours after removal
Methadone
Opioid agonist (mu, kappa, delta)N-methyl-d-aspartate (NMDA) antagonistInhibits reuptake of serotonin and noradrenalinNociceptive and neuropathic pain
Analgesic effect 30-60mins
Duration 4-6hrs
T1/2 8-100+ hrs (~30hrs)
Peak 1.5-3hrs
Large Vd, 80% bioavailability, large protein binding
Accumulates in chronic use
Metabolized in liver, eliminated in urine and feces
Multiple drug interactions
Side Effects of OpioidsNausea (50-70%) and Vomiting (15-20%)ConstipationSedationConfusionRespiratory depressionUrinary retentionPruritus↑ Qt with methadone
Other Medications (our cheat sheet)
Questions