Choosing an opioid for patients at risk​

Unless otherwise appropriate, start with weaker opioids, such as codeine or tramadol. They are effective for chronic pain and have a lower addiction and overdose risk (Dasgupta et al., 2006; Dhalla et al., 2009; Furlan et al., 2006).

If more potent opioids are required, choose an opioid that:

• the patient has not previously used problematically
• is not commonly misused in your local community
• has a lower misuse liability.

Determining the right dose for patients at high risk

Careful titration is recommended with patients at high risk of addiction because the euphoric effects of opioids and the risk of overdose are dose-related (Lamas, 1994).

The Canadian Guideline for Safe and Effective Use of Opioids for Chronic Non-Cancer Pain (National Opioid Use Guideline Group [NOUGG], 2010) recommends a "watchful dose" of 200 mg morphine equivalent per day. Controlled trials have shown that the majority of patients get adequate pain relief with doses well below 200 mg (Furlan, 2006).

Optimal dose

The Canadian Guideline defines the optimal dose as one that relieves pain by at least 30 per cent (about 2 points on an 11-point scale [0–10]) and/or improves function, and where additional dose increases cause minimal additional pain relief.

Titration

Specific titration protocols are outlined in the Canadian Guideline. With each dose increase, the patient should produce a graded analgesic response (e.g., the pain will reduce from 8 to 7 out of 10). Doses should not be increased beyond the watchful dose of 200 mg morphine equivalent daily.

See Oral opioid analgesic conversion and Equivalence between oral morphine and transdermal fentanyl.