Table Of Contents
Opioids
Opioids binds to opiate receptors (mu, kappa, and delta), which are invovled in analgesia, sedation and dependence. They are commonly administered intravenously (appear as needle marks forming a track on physical exam) or inhaled (increasingly smoked with cannabis nowadays). Most patients with acute intoxication will present with coma/death, since different formulations with different concentration exists. For patients abusing prescription opioids, behaviors such as losing medication, consulting multiple doctors and running out of medication early should raise the alarm for possible misuse.
Commonly used opioids
| Opioids | Examples |
|---|---|
| Prescription | Oxycodone (OxyContin), Vicodin (hydrocodone/acetaminophen), Percocet (oxycodone/acetaminophen) |
| Non-prescription | Heroin |
- Signs and symptoms of intoxication
- Drowsiness
- Nausea and vomiting
- Constipation
- Slurred speech
- Constricted pupils
- Seizures
- Respiratory depression → coma/death
- Signs and symptoms of withdrawal
- Dysphoria
- Insomnia
- Lacrimation
- Rhinorrhea
- Yawning
- Weakness
- Sweating
- Piloerection
- Nausea/vomiting
- Fever
- Dilated pupils
- Abdominal cramps
- Arthralgia and myalgia
- Hypertension
- Tachycardia
- Craving
- Treatment of acute intoxication
- ABCs
- Naloxone to reverse respiratory depression (may cause severe withdrawal in an opioid dependent patient)
- Admission to the ICU for ventilatory support may be needed
- Treatment of withdrawal
- Monitor the degree of withdrawal using Clinical Opioid Withdrawal Scale (COWS)
- Clonidine: for in-patient symptomatic treatment (autonomic signs and symptoms)
- NSAIDs: symptomatic treatment (pain)
- Dicyclomine: symptomatic treatment (abdominal cramps)
- Detoxification with buprenorphne or methadone for severe symptoms
- Methadone for opioid use disorder
- Initial doses of 15-30mg are used.
- Then increased by 10-15mg every 3-5 days until 50-80mg is reached.
- Doses are then increased gradually as tolerated and cravings decrease.
- Typical effective dose is 80-100mg.
- For patient in withdrawal: if patient is in a methadone program, start 10mg below current level. If not, start at 10-30mg, whatever dose cures withdrawal symptoms. Continue dose for 7-14 days. Then decrease dose 10-20% Q1-2 days over 2-3 weeks.
- Buprenorphine for opioid use disorder
- It is typically started at 4-8mg on day 1.
- On day 2, dose is increased to up to 16mg.
- During the 1st week, dose can be increased daily to a dose of about 32 mg.
- Most patients are stabilized on 16-24mg. Withdrawal symptoms are absent, opiod misuse is diminished or absent, and cravings are minimized.
- For patient in withdrawal: Initiate 12-48 hours after last use of opiate when in early withdrawal at 4-8 mg. May be increased to 16mg, if patient not responding. Continue dose for 2-5 days. Then taper fose 10-20% Q1-2 days over 2 or more weeks.
Methadone vs buprenorphine vs naltrexone for Opioid Use Disorder
| Drug | Methadone | Buprenorphine | Naltrexone |
|---|---|---|---|
| Mechanism | Long-acting opioid receptor agonist | Partial opioid receptor agonist | Competitive opioid antagonist (precipitates withdrawal if used within 7 days of heroin use) |
| Advantages | Once daily dosing, higher retention and cheaper than buprenorphine | Sublingual ROA is safer and makes overdose unlikely. Can be combined with naloxone (as suboxone) which prevents intoxication from intravenous injection | Once daily dosing or montly depot (long-acting injection). Good choice for highly motivated patients |
| Disadvantages | Can cause QTc prolongation (needs a screening EKG for patients with risk, hence dose is limited to a maximum of 100mg) | More expensive, less patient retention than methadone | More difficult to achieve compliance |
