A third of people with long term health conditions have not collected a prescription due to the cost, it has been warned.
Labour's Tonia Antoniazzi warned that fears over the price of medication - at £9.35 per item - are leading to many either skipping or reducing their doses.
The findings come from research from the Prescription Charges Coalition, a group of 50 organisations calling on the government to scrap the prescription charges for people with long term conditions in England.
Ms Antoniazzi said it is the “tip of the iceberg” that people with “complex, lifelong conditions” are forced to shed out a fortune on prescription charges.
She said the list of people who are exempt from paying a fee for medicines is “woefully out of date”.
The Labour MP, who called a debate in parliament on prescription charges on Monday, said: “Apart from the addition of cancer in 2009, the list has not been reviewed since 1968.
“It also doesn't cover several life changing conditions and I’ll list them: Parkinson's, Arthritis, Asthma, Crohn's Disease, Cystic Fibrosis, Lupus, or Motor Neurone Disease.”
Ms Antoniazzi's debate was organised in response to a petition calling on the Government to continue free prescription access for everyone over 60.
It is currently considering raising this to age 66 - a move that has caused huge backlash.
Ms Antoniazzi highlighted research showing that the NHS could save more than £20million per year if it scrapped prescription charges for people with Parkinson’s and inflammatory bowel disease alone.
It would also reduce pressure on the NHS by preventing health complications that occur when people do not take their medication, the 2018 York Health Economics Consortium study found.
“Instead, the Government is discussing introducing additional charges - that flies in the face of common sense,” Ms Antoniazzi said.
Labour MP Taiwo Owatemi, who is still practising as a pharmacist, said: “Older people have contributed to our society their whole lives, and they have trusted that if they work hard and pay their taxes, they will be looked after.
“That is the deal we make with them, and it is what they expect from us when they get older. The Government’s proposal will break that trust.
“We cannot afford to abandon older people now simply because the Government has decided that this is the best way forward. Doing so will impact trust in the long term.”
Shadow minister for public health Andrew Gwynne said: “The next Labour Government will give the NHS the tools, staff and technology it needs to treat patients on time and to put prevention right at the heart of everything it does.
“I really hope that the Government understands the concern, worry and anxiety of those over 60 in England, who are concerned that their free prescriptions may come to an end.
“They want assurances that the Government gets the reason why prescriptions are free for the over-60s and…that their free prescriptions are not at risk and that we will not face people who cannot afford their medication with the dilemma of whether to heat their homes, feed their families or get the medication they so desperately need. Britain is better than that, and I hope the Minister has some positive news for us.”
Health minister Neil O’Brien said “no decision had been made” on raising the age at which people get free prescriptions and that a consultation was still ongoing.
He said: “We want to ensure that everyone across the country, especially those affected by the cost of living pressures caused by the Russian invasion, can afford their prescriptions.
“That is why we have thought long and hard about how best to balance the needs of those in the affected age group, many of whom will find that they have additional health needs compared with when they were younger, with the pressures facing the public finances.
“I can, however, assure Members that we will respond to the consultation in due course.”
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