Long-term opioid therapy has low rate of addiction
When attempting to relieve pain, GPs must avoid both undertreatment, with the risk of inadequate symptom control, and overtreatment which may cause a range of problems including iatrogenic addiction.
Overtreatment is a problem in the treatment of chronic non-cancer pain with opioids and the current BNF warns that repeated administration of opioids for pain may cause dependence and tolerance.
A systematic review, in the Journal of Pain and Symptom Management, has looked at the clinical evidence regarding the treatment of chronic non-cancer pain for at least six months and found that the risk of iatrogenic addiction is low.
A total of 17 studies were included. However, there were no placebo-controlled randomised controlled trials and 16 were open label, single-arm studies. The authors excluded studies in which data were collected retrospectively because of potential reporting bias.
A total of 3,808 patients were included in the review. Patients had chronic pain and treatment with non-opioid analgesics had failed.
The studies included patients on oral, transdermal and intrathecal therapies.
The quality of data was assessed using a tool designed specifically for the review.
The review found that many patients withdrew from treatment, either because of ineffective analgesia or the unwanted effects of treatment. However, pain scores were reduced in patients who continued treatment.
Only a tiny proportion of patients (0.05%) showed any sign of addiction and only 0.43% could be considered to have misused their medication.
GPs may be reluctant to treat longstanding pain with opioids when an illness is not terminal. If chronic non-cancer pain is opioid sensitive, and there are minimal adverse effects, fear of iatrogenic addiction should not prevent the use of opioid analgesics.
Long-term Opioid Therapy for Chronic Noncancer Pain: A Systematic Review and Meta-Analysis of Efficacy and Safety. J Pain Symptom Manage 2008 doi: 10.1016/j.jpainsymman.2007.03.015Reviewer
Dr Jez Thompson
Former GP, Clinical Director, Leeds Community Drug Services