A painkiller for cancer patients which may no longer be available on the NHS under cost-cutting plans has been dubbed as an essential medicine by global health leaders.
The World Health Organisation (WHO) has added fentanyl, a strong painkiller that comes as patches, to its Essential Medicines List.
But earlier this year it emerged that NHS officials in England were considering it for removal from the NHS prescription list.
In March, NHS England said it will launch a consultation as it works to develop new national guidelines to stop GPs prescribing medicines and other items which are available over the counter for a fraction of the cost.
The guidelines for clinical commissioning groups (CCGs) will initially be developed around a set of 10 medicines including fentanyl, omega-3 and fish oils, lidocaine plasters, gluten-free foods and travel vaccines.
The 10 items are estimated to cost the health service £128 million each year.
Fentanyl is often given to cancer patients to provide pain relief at the end of their life.
WHO has now added the painkiller to its Essential Medicines List, saying the move aims to increase access to medicines for end-of-life care.
The list, which was first developed in 1977 and is updated every two years, is used to help countries make decisions about which products they ensure are available for their populations.
"Safe and effective medicines are an essential part of any health system," said Dr Marie-Paule Kieny, WHO's assistant director-general for health systems and innovation.
"Making sure all people can access the medicines they need, when and where they need them, is vital to countries' progress towards universal health coverage."
NHS England said the consultation has not yet begun.
Commenting on the news, Dr Rosie Loftus, joint chief medical officer at Macmillan Cancer Support, said: "The fact that the WHO are describing fentanyl as an essential drug underlines its importance for cancer patients who are at the end of their life.
"Fentanyl is given to dying people to provide crucial pain relief, and for some it might be the only or best medication that can help ease pain in their final days.
"We were disappointed to learn earlier in the year that the NHS was considering removing prescriptions for fentanyl.
"We are aware of the financial strain the health service is under, but this drug can play an indispensable part in making sure that dying people experience as little discomfort as possible."
Fentanyl skin patches are one of a number of additions to the Essential Medicines List.
WHO officials have also recommended that pre-exposure prophylaxis (PrEP) - taken with tenofovir, alone, or in combination with emtricitabine or lamivudine - should be put on the list to prevent HIV infection.
The drug, described as a "game changer" in the fight against HIV and Aids, has been shown to reduce the risk of infection in people who are at high risk by more than 90%.
In December last year NHS England announced it would fund a trial of PrEP, with at least 10,000 participants over the next three years.
The announcement followed on from legal proceedings which resulted in the health authority losing a "who pays" legal battle in the Court of Appeal.
Three appeal judges upheld a High Court ruling which said NHS England did have the power to fund the drug despite its pleas that the responsibility lies with local authorities.
Meanwhile, other items added to WHO's Essential Medicines List included medicines for hepatitis C, tuberculosis and leukaemia.
The list also includes new advice on which antibiotics should be used for common infections and which should be reserved for the most serious circumstances.
Professor Helen Stokes-Lampard, chairwoman of the Royal College of GPs, said: "Growing resistance to antibiotics is a serious threat to our patients' health worldwide, so we welcome the World Health Organisation taking action to help curb this.
"GPs and other prescribers must have access to guidance and tools that help us prescribe safely for all conditions, in the best interests of individual patients and public health globally - and this updated Essential Medicines List should be useful in our daily practice."