An unprecedented medicines shortage in the NHS is endangering lives, pharmacists have said, as unpublished figures reveal that the number of products in short supply has doubled in two years.

A treatment for controlling epileptic seizures was the latest to be added on Wednesday to a UK drugs shortage list that includes treatments for conditions ranging from cancer to schizophrenia and type 2 diabetes.

Causes of the crisis are thought to include the plummeting purchasing value of the pound since the Brexit referendum, which reduces the NHS’s ability to source medicines abroad, and a government policy of taxing manufacturers.

According to the British Generic Manufacturers Association, there were 111 drugs on a shortages list on 30 October last year and 96 on 18 December, with supply notifications issued for a further 10 treatments to NHS providers in the UK since then.

It analysis suggests a 100% increase in shortages compared with January 2022, with pharmacists and health charities claiming the conditions of some patients were deteriorating as a result.

Delyth Morgan, the chief executive of Breast Cancer Now, said her organisation had been contacted over the past 12 months by several patients unable to source the medicines they needed to control the spread of their disease.

She said: “Last year many people shared with us, via Breast Cancer Now’s helpline, that they’d been facing difficulties accessing their hormone treatment including letrozole, anastrozole and tamoxifen, causing them huge worry and anxiety. Trying to track down a treatment by travelling to a number of different pharmacies is an added burden for patients at an already difficult time.

“It may also sometimes be that certain brands of drugs are out of stock and people may have to switch to another brand or different drug. In the worst case someone may have a period of time without the medication, a drug which could help reduce the risk of their breast cancer coming back or spreading.”

Douglas Twenefour, the head of care at Diabetes UK, said: “The ongoing shortages of many GLP-1 medications are having serious implications for many people with type 2 diabetes and are still a major concern. With these shortages likely to last for at least the rest of this year, this will have a significant impact on whether many people with type 2 diabetes can access the best course of treatment for them.”

The war in Ukraine and problems in global supply chains have generally affected many European countries’ drugs supply, with concerns being raised about fresh market instability in light of the violence in the Red Sea, a key shipping corridor for vital ingredients.

The EU, of which the UK is no longer a member, recently agreed to create a stockpile for key drugs and to invest in increased domestic production.

There have been well-documented shortages in hormone replacement therapy and attention deficit hyperactivity disorder products due, in part, to higher demand.

Janet Morrison, the chief executive of Community Pharmacy England, said the shortages were unprecedented and were beginning to hit patients hard. “Pharmacy teams have been struggling to get hold of prescription medicines for many months but the problem is now worse than ever,” she said.

“It has become worryingly normal to see hundreds of medicines affected by pricing and other issues every month, with problems now a daily occurrence for pharmacies. Pharmacies are having to spend hours – on average an extra 11 hours a week – tracking down the medicines their patients need.

“This all causes worrying delays for patients, and in worst cases it can lead to a deterioration of their health: last year we surveyed people working in pharmacies and 87% told us that their patients’ health was being put at risk due to medicine supply issues. This is shocking, and government and the NHS must step in to resolve these issues.”

The NHS is increasingly having to issue price concessions on products under which it agrees to increase its level of reimbursement to pharmacists due to spikes in demand and market prices.

There were 152 such concessions in December 2023 compared with 20 in June 2016, the month of the Brexit referendum, when the UK’s stated intention to leave the EU hit the value of sterling.

There are also concerns that a government policy to limit NHS spending on branded drugs is having an effect on the pharmaceutical industry’s willingness to invest in supplying the UK. There is a cap on the total allowed sales value of branded medicines to the NHS each year, which grows at an agreed rate of 2% per annum.

Any medicine sales above the cap are paid back to the government via a levy charged on companies’ sales revenues. A scheme with a 4% cap has been introduced for the next five years after consultations with the pharmaceutical industry.

Morrison said the government was underinvesting in drug supply.

She said: “Price concessions are a sign that companies won’t, or can’t, supply a type of medicine at the price that officials previously thought would be enough. Although they show that the system is responding, they are a symptom of the squeeze that brings disruptions and shortages.”

Mark Dayan, the Brexit programme lead at the Nuffield Trust, said there was evidence of a drop-off in medical imports from the EU since Brexit that suggested companies had responded by changing their supply chains, potentially leaving the UK more exposed to supply issues.

He said: “For the UK, this situation has been exacerbated by pressures on drug prices from 2016, probably associated with the Brexit referendum pulling down the value of sterling.

“A payment mechanism to claw money back from companies when sales rose too high saved the NHS money, but it reduced the incentive to sell branded products here.

“In the last two years, being outside the single market has added costs at the border with the EU, resulting in a drop in products passing into this country.”

A DHSC spokesperson said they did not recognise the figures provided by the British Generic Manufacturers Association.

He said: “There are a number of reasons that a limited number of medicines may be unavailable, such as manufacturing difficulties, supply of raw materials, sudden demand spikes or issues with distribution.

“The department has well-established procedures to deal with such issues and works closely with industry, the NHS and others to prevent shortages, and resolve any problems as soon as they arise.

“This includes working closely with the NHS so they can put suggested plans in place to mitigate the risk of the shortage impacting patients.”