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Is the co-proxamol ban harming patients?

The decision to withdraw co-proxamol was cruel and has left many patients with inadequate pain control, argues rheumatologist Dr David Walker. Dr Peter Frith counters that most patients can be managed on alternative analgesia and that GPs do have options even for the most difficult cases.

The decision to withdraw co-proxamol was cruel and has left many patients with inadequate pain control, argues rheumatologist Dr David Walker. Dr Peter Frith counters that most patients can be managed on alternative analgesia and that GPs do have options even for the most difficult cases.

Yes

The Medicines and Healthcare Products Regulatory Agency announced that co-proxamol would be phased out over a three-year period from January 2005.

That is now starting to bite, as the three years is up. The reasoning was that co-proxamol can be very dangerous in overdose and showed no advantage over paracetamol in pain-relieving studies.

The first point is valid, but there are many other drugs that are dangerous in overdose that no one is suggesting should be withdrawn. The second point is, I think, less clear.

When tested in a trial involving lots of patients, most analgesics and indeed most anti-inflammatories look similar to each other.

What is not captured in this aggregated data is the huge variation in the response of individuals to drugs. This applies to both efficacy and tolerability and is obvious to doctors who use these drugs regularly.

To demonstrate this variation in effectiveness in different individuals requires n=1 studies, but the MHRA is not interested in such research findings, which we're told do not count.

Individual data is, however, the only data most patients have any interest in and is exactly the data on which most decisions to change analgesic are based.

On the basis of such data, there would be many patients who find co-proxamol to be effective and tolerable and indeed many who would find it the best drug for them.

To simply say paracetamol is as effective as co-proxamol is far too simplistic and no justification for the withdrawal.

It is perfectly reasonable for a regulating agency to make a decision that having less of a drug in the community would be beneficial to the community as a whole.

Whether the suicide data on co-proxamol, which was largely in people with non-specific pain, merits this decision is a matter for it.

Unreasonable

What is not reasonable is for co-proxamol to be taken from people for whom it has proved to be a tolerable and effective drug, and where the benefit-risk for them is strongly in favour of continuing on it.

The MHRA and its predecessors have allowed patients to be exposed to the drug. Individuals may like it and be unlikely to take an overdose, so on what basis is it fair to take the drug away in case someone else might take an overdose?

It was clear in our clinic that many patients were struggling to find suitable alternatives, hence we did an audit1.

We found almost half had been changed to analgesics that they found less satisfactory. These ranged from paracetamol right up the analgesic ladder to MST continuous.

Only 20% were content on a new drug and the remainder were still getting co-proxamol.

So a majority of patients who were taking co-proxamol, and were presumably happy on it, have been disadvantaged.

This is cruel. It would not be nearly as bad if they had never been exposed to the benefits of it. Our audit population was at low risk of suicidal ideation.

It would have been fairer to stop new prescription of co-proxamol, to expect current users to try at least two other drugs, but for those who found co-proxamol the best, to continue supply.

The regulators have failed to do this and so there are many patients who are not on optimal treatment. Co-proxamol should retain a key place in the analgesia of at least these patients.

Dr Walker is a consultant rheumatologist and honorary clinical senior lecturer at Newcastle University

 

No

The withdrawal of co-proxamol continues to pose therapeutic and ethical dilemmas for us all.

The regulatory agency decided to suspend the licence at the end of 2007 following a paper on the risks posed by the drug in the BMJ2.

The research showed co-proxamol was second only to tricyclic antidepressants in being responsible for fatal overdoses – and was associated with an average of 255 fatalities each year.

It was also 2.3 times more likely to be fatal in overdose than tricyclics and 28 times more so than paracetamol alone.

But in fact concerns over the safety of co-proxamol had first been raised more than 20 years earlier3, so the previous actions taken by GPs and the regulatory authorities had clearly not been effective.

We all know co-proxamol contains a combination of paracetamol and dextropropoxyphene. But the dose of paracetamol in two tablets of co-proxamol is only 650mg – not a full therapeutic dose.

There is evidence that full-dose paracetamol is as effective as co-proxamol in relieving pain3.

Admittedly, Dr Walker argues that some patients do not find this to be the case, even when an equivalent mild opiate is co-prescribed1, perhaps because of differences between the treatment of chronic versus acute pain.

But my experience is that it is possible to successfully reduce co-proxamol prescribing without causing widespread dissatisfaction among patients.

Following the publication of the paper in the BMJ, my practice reviewed its co-proxamol prescribing with the support of our local PCT prescribing adviser and her team5.

First, we agreed not to initiate new co-proxamol prescriptions. Second, we asked all our patients to try changing to paracetamol.

If this was not satisfactory we asked them to try a paracetamol/codeine (or equivalent) combination. If this was unsatisfactory, we returned to co-proxamol.

This approach allowed us to reduce our co-proxamol prescribing by about 80%.

Following the MHRA's decision, we revisited our prescribing using the same approach, explaining to patients the reasons for the withdrawal of the drug's licence.

We reduced our number of patients on co-proxamol to under 20 (from an initial figure of more than 400), and this has now come down to single figures.

Surprised

I have to say I was surprised by how little patient dissatisfaction was generated, perhaps showing the differences in case mix between general practice and a rheumatology clinic.

I do have some misgivings about the MHRA's advice on alternative analgesia to co-proxamol.

My understanding is that it advocates the use of NSAIDs from step two onwards unless they are ‘contraindicated or not recommended', which I worry about because of their many side-effects.

It is also ironic that the advice includes use of tricyclics, thus substituting the drug second most commonly associated with fatal overdose with the first!

Whether the MHRA took the right decision to suspend the licence I'm not sure, but certainly the actions taken earlier had not been effective.

There is evidence that action at PCT level to reduce co-proxamol prescribing is effective5.

I wouldn't want to belittle the situation some patients are in, and Dr Walker's article is articulate in making this point.

But my own view is that in a general practice setting, relatively few patients are in this predicament, and these can be successfully managed either by reverting to co-proxamol (on a named-patient basis) or through advice from pain clinics.

I don't think we are being cruel to our patients when we have these options available to us.

Dr Frith is a GP in Mansfield Woodhouse, Nottinghamshire

Co-proxamol

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Readers' comments (1)

  • What an interesting article ! However, now in 2016, it is clear that the alternatives have NOT successfully replaced Coproxamol. Prescriptions & costs for other opioids have rocketed, concerns regarding the risks associated with Tramadol have obliged the MHRA to schedule it, & the relationship bewteen many GPs & their patients has been damaged ! In the meantime, thousands of mainly disabled & elderly chronic pain sufferers' lives are a misery because of inadequate pain relief !!

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