Patients claim they have been left in pain following a decision to make it harder to get a commonly used drug.
Specialists said painkiller coproxamol was responsible for hundreds of fatal overdoses a year.
The Medicines and Healthcare products Regulatory Agency removed the drug's licence in January, although this did not mean a complete prescribing ban.
However, some patients say alternatives do not work, and their GPs are not prepared to offer an unlicensed drug.
The drug, a mixture of paracetamol and an opioid drug, has been available since the 1960s, but its licence was withdrawn because it was too easy to overdose on it.
Coproxamol has been linked to fatal overdoses
This still gave GPs the option to prescribe it "off-licence", although this is considered a greater legal risk in the event of side-effects or complications.
However, for some patients - such as those with chronic back pain, arthritis, or sciatica - coproxamol was the most effective drug available.
Jenny Purle, who was diagnosed with rheumatoid arthritis at just 13, can no longer get the drug, and is now in greater pain than before.
She said: "I've got about a dozen and they're like gold dust to me. If I'm at screaming point then I will take a couple.
"Coproxamol wasn't a magic wand - but it was the closest thing I had."
She now has to take a cocktail of drugs to control her pain.
"I am taking pills to counter-act the pills, to counter-act the pills. How far do you take it?"
The charity Arthritis Care said it received calls from patients with no effective alternative to coproxamol.
A spokesperson said: "We urge the MHRA to consider re-licencing coproxamol for these people or at the very least, progress must be made on ensuring people can access it on a named-patient basis.
"Otherwise many people will be looking at a bleak future of unrelenting pain."
However, Professor Nick Bateman, from the University of Edinburgh, backed the decision to remove the licence.
"The truth is that in the UK for the past 10 years or more somewhere between 200 and 300 people have been dying every year from accidental ingestion, perhaps from overdose, many of them old or confused or vulnerable young people - often people who weren't actually prescribed the drug at all - and that's the target of this change."
Dr June Raine, from the MHRA, said that the move was already saving hundreds of lives a year, and denied that doctors were confused about its status.
She said: "We have always accepted that some patients will need co-proxamol, and that is why supplies are being assured.
"The doctor has to make a judgement that using the drug is in the patient's best interests."
GP Rosemary Leonard, who sat on the expert panel which eventually decided to remove coproxamol's licence, is continuing to prescribe the drug to some of her patients, even though the cost to her primary care trust has risen from 20p a box to £20 a box since the change.
She said that the lives saved had to be balanced against the likely increase in the number of patients who needed hospital treatment for stomach problems as a result of taking anti-inflammatory painkillers such as ibuprofen as an alternative.
I have taken coproxamol in the past during severe arthritis flare-ups and it's the only thing which helped me. Arthritic pain is draining and constant and I seriously question whether those who made the decision have ever experienced such pain. When it is so constant you start to become very despondent about life and can slip into a depression, how is that beneficial? Claire, Buckinghamshire
After I had my babies by caesarean (15-20 years ago), I took coproxamol for the post-operation pain. Coproxamol was the only thing that worked - nothing else came close. I feel sorry for those people who need coproxamol and cannot get hold of it. Susan, Hertfordshire
I take this drug as I suffer from osteoarthritis and will be in very severe pain without it. Ibuprofen is no good to me as it burns my stomach causing severe problems. I've tried other painkillers to no avail so all that's left for me is codeine or morphine which I am reluctant to take. This is another ploy for the government to save money as there are so many people reliant on these drugs. David, Edinburgh
I have suffered with rheumatoid arthritis since the age of five and was first prescribed coproxamol in the mid seventies. It is an excellent painkiller and enabled me to cope and continue to go to school. I am now 46, I still have rheumatoid arthritis, it never goes away and the only effective painkiller I have ever used is coproxamol. It seems so unfair, when life is already a struggle to have one of my major resources removed. I have managed my own drug regime since I was 12 years old, now me and thousands like me are told we cannot be trusted. Debbie, Cheshire
I suffer from intermittent back pain and last had a bad episode about three months ago when the doctor agreed to prescribe me coproxamol. Not only that, she prescribed me two boxes of 100 each. When I had to go and see the emergency doctor a few days later as the pain got worse, she could not believe I had been prescribed so many. Richard, Bathgate
I don't take coproxamol but I have been asked to prescribe it. Our politicians think that they can design out every risk with a new law. They forget that anyone seriously wanting to kill themselves will find a way. The problem for me is that the change in the regulations has raised the cost of a packet of 100 coproxamol tablets from less than £2 to almost £30. Is that cost effective for our drugs budgets when there are certainly some people who do better with this drug than others available? Philip, Crowborough
I have suffered with sciatica for years but am still relatively young with a young child. I have a supply of coproxamol from years ago which I am using since my other effective pain killer was also banned, for the perfectly laudable reasons that it increased the risk of heart attack. Whether through side effects, self-poisoning or accidental overdose, powerful drugs will result in regrettable fatalities but this leaves a great many of us - who can accept the risks in exchange for a better quality of life - debilitated and in constant, ever more severe pain as our effective pain relief is denied us. Simon, London
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