Acute Opioid Withdrawal in the Emergency Department

How to Cite This Chapter: Bérczi B, Martin L, O’Shea T, Klimaszyk D, Kołaciński Z, Szajewski J. Acute Opioid Withdrawal in the Emergency Department. McMaster Textbook of Internal Medicine. Kraków: Medycyna Praktyczna. Accessed June 19, 2024.
Last Updated: June 7, 2020
Last Reviewed: January 28, 2021
Chapter Information

Clinical FeaturesTop

Patients usually develop clinical symptoms of withdrawal 6 to 48 hours after opioid discontinuation (6-12 hours for short-acting agents and up to 24-48 hours for methadone or fentanyl; remember that fentanyl accumulates in fat cells with prolonged use, leading to a prolonged half-life [see Opioids and Opioid Use Disorder: General Considerations]) or after a significant dose reduction of their opioid. However, the onset of symptoms may be precipitated by the use of an opioid antagonist (eg, naloxone). In most cases the syndrome of withdrawal persists for anywhere from a few days to weeks.

Symptoms: Malaise, weakness, pain, muscle twitching, chills, nausea, stomach cramps, anxiety, aggression, insomnia.

Signs: Elevated blood pressure, tachycardia, elevated body temperature, dilated pupils, lacrimation, excessive sweating, diarrhea, vomiting, rhinorrhea, piloerection (goose bumps), sneezing, yawning.


Several useful tools are available for assessing withdrawal severity in the emergency department. The Clinical Opiate Withdrawal Scale (COWS) is one such score (see Opioids and Opioid Use Disorder: General Considerations).


The provided trade (brand) names are valid for Canada.

1. Ensure clinical stability: Assess vital signs, exclude potentially overlapping presentations (alcohol withdrawal, sepsis, intoxication with another substance).

2. Determine the severity of opioid withdrawal: Using the COWS determine the severity of opioid withdrawal. For mild withdrawal, offer withdrawal-associated symptom management; for moderate to severe withdrawal, offer opioid agonist therapy (OAT). Details: see Opioids and Opioid Use Disorder: General Considerations.

3. OAT: Buprenorphine/naloxone (brand name Suboxone) should be offered within 2 hours of presentation in patients with moderate to severe opioid withdrawal. Do not offer buprenorphine/naloxone in the emergency department if the patient has a history of prolonged fentanyl use and last use occurred within 24 hours, unless you have expertise in using this medication in these circumstances.

In most jurisdictions physicians do not require an exemption to prescribe buprenorphine/naloxone, but it is important to be knowledgeable about this medication. Please consult your local regulatory guidelines (eg, from the College of Physicians and Surgeons of Ontario). A traditional buprenorphine/naloxone induction protocol is detailed below. Increasingly, those with expertise in prescribing buprenorphine/naloxone are using microdosing protocols. At this time, such protocols are currently off-label and require further study, and thus they will not be detailed here.

1) Dosage in the emergency department:

a) Initial dose: If the patient is confirmed to be in moderate withdrawal using a withdrawal scale (COWS >12), administer buprenorphine/naloxone 2 mg sublingually.

b) Reassess: Repeat the COWS assessment every 1 to 2 hours. If the score increases (withdrawal worsens), the patient may be experiencing precipitated withdrawal (see Opioids and Opioid Use Disorder: General Considerations). Stop the induction and switch to symptom management. Consider moving the patient to a monitored setting and consulting with an addiction specialist if you are concerned. If the score remains the same or decreases, you can administer subsequent doses until the patient is comfortable.

c) Subsequent doses: Administer 2 mg sublingually up to a recommended day 1 total of 8 mg.

2) Prescription: Fax or email a prescription for the cumulative dose delivered on day 1 in the emergency department to a pharmacy of choice for the appropriate number of days until the patient can be reassessed by a physician. Doses should be dispensed daily and witnessed by a pharmacist. Ensure appropriate follow-up is arranged with a physician who is able to continue prescribing as required before discharge from the emergency department.

Other types of OAT, such as methadone or slow-release oral morphine (SROM) (brand name Kadian), are more complex and reserved for prescribers with expertise in the management of opioid use disorder.

4. Symptom management, harm reduction, and referrals/resources: see Opioids and Opioid Use Disorder: General Considerations.

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