The Medicines and Healthcare products Regulatory Agency (MHRA) has launched a consultation into its suggestion that codeine linctus be reclassified as a prescription-only medicine (PoM) to curb its potential for illicit recreational use.
The agency said that it was aware of multiple reports of codeine linctus being used recreationally for its opioid effects, rather than for its intended use as a cough suppressant. Since 2018 it had received 116 Yellow Card reports of recreational drug abuse, dependence, and/or withdrawal to codeine medicines, including codeine linctus.
There are currently two formulations of codeine linctus BP each containing 15mg codeine per 5ml dose and licensed as pharmacy medicines, available to purchase over the counter in pharmacies only. Notwithstanding that, and the current drive to encourage pharmacists' prescribing, the MHRA said that if reclassified as PoM, codeine linctus would require a GP's prescription.
"Significant Concerns" About Misuse and Addictive Potential
Dr Alison Cave, MHRA's chief safety officer, said: "Codeine linctus is an effective medicine, but as it is an opioid, its misuse and abuse can have major health consequences." She said that responses to the consultation would help the agency develop "a broader view" on whether codeine linctus should be restricted to PoM status.
Professor Claire Anderson, president of the Royal Pharmaceutical Society, said the society welcomed the consultation to understand the impact of the potential status change on pharmacists, pharmacy teams, and the public. "Medicines should maximise benefits to patient health with minimum risk," she said.
"We believe there is insufficient robust evidence for the benefits of codeine linctus in treating coughs safely and appropriately, Professor Anderson added. "We also have significant concerns about its misuse and addictive potential, as well as the risk of overdose."
Genetic Risks of Dependence and Toxicity
She added that there were many non-codeine based products available, and that as studies showed up to 60% of people were genetically predisposed to opioid dependence, "the role of codeine linctus in treating what is ultimately a self-limiting condition is questionable".
The European Medicines Agency notes that codeine is metabolised by the liver enzyme CYP2D6 into morphine, its active metabolite. Up to 6.5% of Caucasian populations are ultra-rapid metabolisers, who are at increased risk of developing opioid toxicity even at commonly prescribed doses. General symptoms include nausea, vomiting, constipation, lack of appetite, and somnolence, while severe cases may include circulatory and respiratory depression.
The charity Drugwise advises that as codeine-containing medicines may be habit forming, they should be used for a maximum of 3 days at a time. However it noted that although codeine may be misused, its euphoric effects are less than those of other opiates.
The MHRA said it hoped to hear from "a broad range of individuals", including
health professionals and the public. The consultation will run for four weeks from 18 July 2023 to 15 August 2023.