Module 6: Opioid agonist treatment (OAT) initiation and stabilization phase Flashcards
What is the name of the Canadian guideline for OUD management?
CRISM (Canadian Research Initiative in Substance Use)
(unclear what year)
CAMH also has a guideline: Opioid Agonist Therapy: A Synthesis of Canadian Guidelines for Treating Opioid Use Disorder – Canadian Opioid Use Disorder Clinical Guidelines (2021)
Prescribing practices for narcotics
- written or faxed prescriptions only
- no refills permitted
- dose in mg (write dose in words)
- new start vs dose increase or decrease
- start and end dates (“inclusive”)
- specific days for observed doses
- specific days for carries
- for methadone: “doses should be dispensed in orange juice
- for bup/nlx: “sublingual administration”
- for bup/nlx don’t specific # of tablets, just dose, frequency, duration and allow pharmacist to figure out required number of tablets
Physician requirements for prescribing methadone
> “effective May 19, 2018, exemption is no longer required to prescribe methadone for opioid use disorder”
> CPSO: “As with all areas of practice, physicians must only prescribe methadone if they have the knowledge, skill, and judgment necessary to do so safely and effectively. Physicians and other health-care professionals can obtain the necessary training and education by completing the Centre for Addiction and Mental Health’s Opioid Use Disorder Treatment course and Opioid Dependence Treatment Certificate Program.2”
- In other words: you should do the CAMH training course
Physician requirements for prescribing bup/nlx
nothing mentioned on CPSO
Probably should have training.
Prescription practices when starting / changing dose
“Cancel previous prescriptions”
“Dose change”
What should happen to OAT prescription upon admission to hospital?
Should be cancelled at community pharmacy so that
- admission is communicated
- avoids errors in dose changes / prescriptions
What should be communicated to client at initiation
- effects / side-effects / toxicity / interaction with other opioids
- bup/nlx starts at 2-4mg, requires few weeks to optimum dose
- methadone starts 15-30mg, risk of toxicity
- withdrawal symptoms until dose optimized
- risk reduction: naloxone kit, small doses, do not use alone
- missed doses and apparent intoxication at pharmacy
- written agreement
Buprenorphine time of onset (peak plasma concentration)
1 hour
Buprenorphine half-life
32 hours on average
Initiating bup/nlx: what describes moderate withdrawal?
COWS 13+
Initiating bup/nlx: estimated wait times to moderate withdrawal?
short-acting opioids: 12h+
long-acting opioids: 12-24h+
methadone: 36h to 3-5 days
fentanyl: tricky because it accumulates in fat tissue, risk of precipitated withdrawal
What makes a high risk for precipitated withdrawal when starting bup/nlx in fentanyl users?
accumulates in fat tissue, so effective half-life is prolonged
risk of precipitated withdrawal even when moderate withdrawal sx or 12h+ since last use
initiating bup/nlx: microdosing – the big idea
avoid any moderate-severe withdrawal symptoms by gently introducing partial-agonism of bup/nlx:
1. using full agonist therapy (e.g. methadone)
2. while slowly increasing bup/nlx dose over a week
initiating bup/nlx: microdosing – the protocol
- Start with a low dose of bup/nlx (e.g. 0.5mg) overlapping with other opioid use.
- Implement small (e.g., 0.5–1 mg) daily dose increases of bup/nlx, over five to seven days.
- Cease opioid use abruptly after reaching a total daily dosage of 12 mg of bup/nlx.
initiating bup/nlx: microdosing – target populations
- use illicit fentanyl and fentanyl analogues (b/c unpredictable withdrawal)
- may not reliably attend appointments due to work commitments or social instability
- cannot tolerate moderate to severe withdrawal.
initiating bup/nlx: conventional approach – induction day
if COWS > 13,
0. prescriptions for supportive meds (clonidine, loperamide, dimenhydrinate)
1. client -> pharmacy for first dose
2. returns (not driving self)
3. re-assessed over 3 hours to confirm no precipitated withdrawal
initiating bup/nlx: conventional approach – initial dose
2-4mg
consider also one to two 2mg tabs PRN for withdrawal symptoms
max 12mg total in one day
initiating bup/nlx: conventional approach – titration
day 1: 2-4mg once + 2mg x 1-2 tabs PRN withdrawal
day 2: doubled (4-8mg once), max 24mg po daily
day 3: doubled again (8-16mg once), max 24mg po daily
etc.
stop when no withdrawal x 1 day
initiating bup/nlx: conventional approach – titration – elderly
slower titration:
increase by 2-6mg every one to two days max 24mg daily
same stopping criteria: stop when no withdrawal x 1 day
long-acting bup: formulations
implants (q6month, abstinence prior, up to 8mg SL daily)
subq (qmonthly, no abstinence required, 8-24mg SL x 7 days prior)
methadone – time to steady state
5-10 days (half life 36 hours on average)
methadone – initiation – key determinate to chose starting dose
risk of methadone toxicity
high risk = low opioid tolerance (i.e. low potency use, low frequency use)
methadone – initiation / titration – high risk of toxicity
high risk: low potency use, low frequency of use
max 10mg, then increase by 5mg every 5 days
methadone – initiation / titration – moderate risk of toxicity
moderate risk: established tolerance (by UDT/hx), high risk factors for resp depression (COPD, depressant use, elderly)
5-20mg, then increase by 5-10mg every 3-5 days
