From Thursday drugs containing codeine – an addictive substance closely related to morphine and derived from opium – will no longer be available from pharmacies without a prescription.

The imminent change to regulations for codeine products has prompted renewed praise for the Therapeutic Goods Administration for taking action to address Australia’s growing opioid crisis, though some health experts are concerned the move may have unintended consequences, such as pushing people towards illicit products.

The change will affect drugs such as Nurofen Plus and Panadeine, which are considered low-dose codeine-containing medicines. Drugs containing more than 30mg of codeine already require a prescription.

Like many countries, Australia is experiencing a concerning rise in intentional and accidental codeine-related deaths. A study led by the University of New South Wales found that, over the 10 years to 2009, deaths with codeine as an underlying cause more than doubled from 3.5 per one million people to 8.7. The study found those who died from accidental overdose were more likely to have also taken other substances and to have had a history of substance abuse problems and chronic pain.

According to the TGA, one of the reasons accidental codeine overdoses are at record levels is “indication creep” – codeine being used for an ever-increasing range of conditions, such as chronic non-cancer pain, despite limited evidence of its efficacy for those conditions. Last week, the TGA announced it was considering barring general practitioners from prescribing stronger opiates, meaning only specialists would be able to prescribe the drugs.

Dr David Caldicott, an emergency consultant and senior clinical lecturer in medicine at the Australian National University, said for the overdose crisis to be addressed, opioid use needed to be restricted across the board, not just at the over-the-counter level. Patients being prescribed strong opioids after surgery were also becoming addicted, he said, and he agreed with TGA concerns that general practitioners were relying too heavily on the drugs.

But Caldicott fears that cutting people off from accessing opioids without other support systems in place could have disastrous consequences. Other countries that already restrict codeine access, such as the US and parts of Europe, were nonetheless experiencing rising opioid-related death rates, he said.

He believes a national, real-time monitoring system for patients prescribed codeine and opiate products, and improved access to and education about other forms of pain relief, such as medicinal cannabis, are needed to mitigate the risk that patients will fall through the cracks and turn to other drugs and illicit substances. When low-dose codeine products become prescription-only, the real-time recording system currently used by pharmacists to record the details of patients buying drugs containing codeine will be discontinued.

“People are talking a great deal about limiting access to opiates, which is the right conversation,” Caldicott said. “But I haven’t seen a lot of discussion about the consequences of doing that quickly. I am very anti big pharma and anti opiates but, by the same token, I think it’s very important that we think about the downstream effect. A huge part of the problem in Australia is we just don’t know how to effectively treat chronic pain and it is easier for doctors to write a script than look at alternatives.

“But when you look at jurisdictions in the US that have implemented a medicinal cannabis system, opiate deaths have been reduced by as much as 30%. If we don’t put alternatives in place here in Australia and ensure people who are in pain and who are reliant on codeine have alternatives, then we are simply pulling the rug out from under them.”

According to the Consumers Health Forum, one in five Australians live with ongoing chronic pain and prevalence of pain is expected to only increase as the population ages.

According to Pain Australia, the latest general practice data shows that an opioid was prescribed in 73% of cases where patients complained of general multisite pain and, between 1992 and 2012, opioid dispensing increased 15-fold. This is despite mixing painkillers with alcohol or other drugs has unpredictable results and is a cause of accidental death.

Clearly, there is a problem with codeine use in Australia and something has to be done to address it, head of forensic sciences at Victorian Institute of Forensic Medicine, Dr Dimitri Gerostamoulos, said. But he is concerned about what the impact of restricting access will be on people in rural areas in particular, who may not have ready access to pain specialists and other treatments.

“What we might end up seeing is an increase in combined medicine use, such as paracetamol and ibuprofen products, and more people accessing codeine made available illicitly,” he said.