Update: August 2017
From 1 February 2018, medicines that contain low-dose codeine will no longer be available without prescription in pharmacies.
A 2015 Australian study investigated codeine-related deaths over a 10-year period. The analysis has shown some worrying trends, with deaths related to codeine use doubling over the study period. Analysis of the characteristics of people who died from codeine-related overdose suggests a complex population of patients who require careful management by prescribers and pharmacists.
- Codeine-related deaths have doubled between 2000 and 2009: Continued vigilance is required to help minimise harm from codeine use.
- Pharmacists have an important role to play in minimising harm: As codeine is available over the counter, pharmacists are an important source of information and advice for consumers.
- Consumer education is essential: All health professionals should endeavour to inform consumers about the safe use of codeine and preparations containing codeine, including the dangers associated with combining medicines.
Implications for practice
Where data were available, more than half of codeine-related deaths involved people who were prescribed codeine.1 However 40% of people had used over-the- counter products and this suggests a serious issue for clinical practice that involves both prescribers and pharmacists.1
The numbers of patients who died from intentional overdose in this study suggests that prescribers should consider screening for depression and suicide risk prior to prescribing codeine. The high prevalence of substance use problems in patients who died from accidental overdose suggests that prescribers need to consider the risk of substance misuse before prescribing codeine, as is recommended for prescribing Schedule 8 substances.2
Prescribers need to be aware that codeine metabolism is dependent on the activity of cytochrome P450 2D6. Genetic variation in this enzyme produces some individuals (about 1%–2% of the white population) who are classed as ultrarapid metabolisers and have a greater risk of adverse events such as respiratory depression and fatal overdose due to the greater conversion of codeine to morphine.1,3 Conversely, poor metabolisers (about 5%–10% of the white population) have little codeine converted to morphine and therefore receive little analgesic benefit.1,3
Patient education is essential whether codeine is prescribed or dispensed over the counter. Pharmacists play a key role ensuring patients understand the potential dangers of codeine, particularly when taken in combination with other medicines (ie, benzodiazepines or opioids). Patients also need to understand the harms associated with combination products, such as paracetamol–codeine combinations or cold and flu medicines.
Potential rescheduling of codeine
The Therapeutic Goods Administration (TGA) has published a proposal to recommend that all over-the-counter medicines containing codeine be rescheduled as prescription-only medicines. The final decision will not be made until late November 2015.4
- Roxburgh A, Hall WD, Burns L, et al. Trends and characteristics of accidental and intentional codeine overdose deaths in Australia. Med J Aust 2015;203:299. [PubMed].
- Expert Group for Analgesics. Therapeutic Guidelines: Analgesic Version 6. Therapeutic Guidelines Ltd, 2012 [eTG online] (accessed 8 October 2015).
- Crews KR, Gaedigk A, Dunnenberger HM, et al. Clinical Pharmacogenetics Implementation Consortium guidelines for cytochrome P450 2D6 genotype and codeine therapy: 2014 update. Clin Pharmacol Ther 2014;95:376-82. [PubMed].
- Therapeutic Goods Administration. Proposal for the re-scheduling of Codeine products. Canberra: Department of Health, 2015. [Online] (accessed 8 October 2015).