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Is your client a candidate for injectable opioid agonist therapy? Guidelines and questions to consider

Resources and advice to help nurses provide safe, client-centred care

By Marlene Haines & Amanda LaBelle
July 3, 2024
An option for people who use drugs is injectable opioid agonist therapy (iOAT). Injection medication may be helpful for people who have not found oral medication to be effective or for people who wish to continue injecting opioids in a safer way.

This article is part of the Canadian Nurse series, Harm Reduction Saves Lives.

Canada is currently in the midst of a drug poisoning crisis. Drugs from the unregulated supply are commonly contaminated with unknown substances such as fentanyl analogues, benzodiazepines and other sedatives, resulting in people having no way of knowing what may be in the drugs they are using. People who use drugs continue to be extremely marginalized and stigmatized. For instance, many people still associate drug use with personal choice rather than a response to complex trauma or unmanaged pain. Providing appropriate, safe, and client-centred care for people who use drugs is an essential component of nursing practice.

Options for people who use drugs

A spectrum of services and programs are needed to provide support to people who use drugs. Safer supply programs are an option to address the harms associated with unregulated drug use. These programs are based on the principles of harm reduction and aim to provide people who use drugs with pharmaceutical-grade prescription medication as a safer option to unregulated drugs with unknown contents (Canadian Association of People who Use Drugs, 2019).

Injectable option for people who use substances

An option for people who use drugs is injectable opioid agonist therapy (iOAT). This therapy is an evidence-based treatment program for individuals with a severe opioid use disorder who are injecting unregulated opioids. iOAT programs provide clients with injectable hydromorphone or diacetylmorphine (pharmaceutical-grade heroin) in a supervised setting.

Injection medication may be helpful for people who have not found oral medication to be effective or for people who wish to continue injecting opioids in a safer way. Doses of medication are provided throughout the day, injected by clients and witnessed by health-care providers, often nursing staff. Clients typically inject their doses of medication intravenously (IV push), although doses can also be administered intramuscularly. iOAT programs are designed to manage clients’ ongoing opioid cravings and withdrawal symptoms.

iOAT is typically offered to clients who want to decrease or discontinue their unregulated opioid use. Common client goals for being on the program may include (1) having safer drug use, (2) mitigating the harms and risks associated with unregulated drug use, (3) decreasing the risk of infectious disease transmission, (4) decreasing participation in criminalized behaviours, (5) decreasing the risk of drug overdose, (6) improving mental and/or physical health, and (7) increasing autonomy and decision-making surrounding drug use. Overall, it is essential for nurses to support clients with their own individualized goals.

iOAT exists along a continuum of care. Some clients may wish to work toward abstinence, whereas others may want to stay on iOAT for the rest of their lives and/or move to other treatment options. Nurses must recognize that abstinence is not always a meaningful or realistic approach to unregulated drug use and that each client will have their own desired outcomes.

iOAT practice guidelines

There are a number of extremely useful and informative iOAT guidelines that nurses can review (for example, the Guidance for Injectable Opioid Agonist Treatment for Opioid Use Disorder from the British Columbia Centre on Substance Use and the National Injectable Opioid Agonist Treatment for Opioid Use Disorder Clinical Guideline from the Canadian Research Initiative in Substance Matters). Common program components include the following:

Program candidacy

Clients are assessed to see if they are a candidate for an iOAT program. Initial doses of hydromorphone1 are determined on a case-by-case basis. Typical starting doses include 60 to 90 mg of IV hydromorphone divided into three to six doses over the course of the day (e.g., hydromorphone 30 mg IV x three doses/day).

Medication adjustments

Over the first week of an iOAT program, doses should be rapidly titrated to optimize the efficacy of the medication and ideally reach a therapeutic effect. Aspects of an iOAT program can vary, such as the number of injections per day, the dose of each injection, and the time between injections. Furthermore, IV doses are commonly paired with long-acting opioid prescriptions (e.g., methadone, slow-release oral morphine) to manage withdrawal symptoms.


Pre- and post-dose assessments are essential components of iOAT programs. Commonly used assessment tools include the Clinical Opioid Withdrawal Scale, the Subjective Opiate Withdrawal Scale and the Pasero Opioid-induced Sedation Scale. Vital signs should be monitored throughout interactions, including respiratory rate and blood oxygen saturation (spO2) levels.


Clients should have regular check-ins with their health-care team to assess the need for dose changes, adjunct therapy, additional wrap-around supports (e.g., primary care, housing workers, counselling), and to evaluate goals. Nurses can offer clients ongoing support to help them work toward their goals.

Commonly asked questions

I am a nurse who will be caring for a client on iOAT for a period of time in the hospital or community. What do I need to do?

It is essential that clients receive their iOAT medication while they are in the hospital. Nurses should speak with the client and their iOAT team to ensure that their medication doses are given on schedule. Delays to administering medication can result in clients leaving against medical advice, experiencing severe opioid withdrawal symptoms, or not receiving the care they need.

Client iOAT prescriptions should not be altered; doses should be given as they would receive them in their iOAT program (e.g., IV doses should be given as an IV push). If nurses have concerns or are unsure, they should speak with the iOAT care team and consult guidelines for more information. Remember that medications prescribed as part of iOAT should be treated as you would other prescription medications.

Discharge back to the iOAT program must include a clear pathway/plan back into the community so that the client’s medication doses are not impacted. Ideally, nurses should avoid discharges on weekends, holidays and evenings to help clients successfully reconnect with their iOAT team.

I am a nurse who will be seeing a client on an iOAT program on a regular basis. How can I best support them?

Nurses should seek to build safe, therapeutic relationships with all clients. They must recognize that people who use drugs face stigma and marginalization within the health-care system and may be hesitant to engage with new care providers. Nurses must apply trauma-informed, client-centred approaches and strive to change the culture of stigma within health care.

If a nurse will be seeing a client on iOAT regularly, they should consider how they can develop a flexible and appropriate care plan in partnership with this client.

This client is receiving more opioids than I’ve ever administered to someone. Should I be worried that they will overdose on the medication I am giving them?

Clients on an iOAT program have an extremely high tolerance for opioid medication. Nurses need to remember that these are witnessed medications the client is regularly receiving and has been tolerating in the community. Importantly, new pain must be addressed as a separate concern and treated with additional medications or therapies. Nurses should complete comprehensive pre- and post-assessments when administering iOAT medication to ensure client safety. Furthermore, nurses can keep naloxone on hand in case of emergency.

Can use diacetylmorphine or hydromorphone, but hydromorphone is more commonly used as it tends to be more accessible via prescription/through drug formularies.


Canadian Association of People Who Use Drugs. (2019, February). Safe supply: Concept document. Retrieved from

Marlene Haines, RN, is a PhD candidate at the University of Ottawa, Faculty of Health Sciences, School of Nursing.
Amanda LaBelle, RN, is a nurse coordinator at Ottawa Inner City Health.