Some patients now have affordable access to a treatment for neuropathic pain, but others do not. These inconsistencies are unfair and have created an ethical dilemma for doctors, reports Dr Michael Vagg, a Consultant in Rehabilitation and Pain Medicine at Barwon Health in Geelong.
(Meanwhile, Dr John Dowden, editor of Australian Prescriber, comments further at the bottom of the post.)
Dr Vagg writes:
“The Federal Government has issued this media release including guidelines on the prescribing for some commonly prescribed drugs including gabapentin. The guideline on gabapentin reiterates the PBS position that neuropathic pain, or pain arising from malfunctioning or damaged nerves, is not able to be treated under the PBS restrictions with gabapentin.
This reads as a sick joke to Australians who are suffering from neuropathic pain and looking for effective treatment. The International Association for the Study of Pain (IASP) has a Special Interest Group on Neuropathic Pain, which has performed an exhaustive review of the available evidence relating to drug treatments for neuropathic pain. It lists five agents as ‘first line’ treatments based an analysis of efficacy, safety and cost-effectiveness. Those drugs are:
1.Gabapentin
2. Pregabalin
3. Duloxetine
4. Amitriptyline and other tricyclic antidepressants
5. Topical lignocaine patches or adhesive plaster
According to the current PBS restrictions, none of these are available to Australians for treatment of neuropathic pain under the PBS. That’s right. None.
In fact the Government is cracking down on the poor GPs, neurologists, pain specialists and rehabilitation specialists who are constantly facing having to manage suffering patients who cannot afford private prescriptions for gabapentin or pregabalin (which can run to over $200 a month).
Cost effectiveness and tolerability studies suggest that all of the first line drugs have comparable acceptability, with the increased efficacy of tricyclic drugs being offset by the greater tolerability of the other drugs in practice. They should all be available for appropriate treatment of this disabling and distressing condition.
Doctors who see many patients with neuropathic pain are faced with a difficult ethical decision. Either they do the right thing by the PBS and require sufferers from chronic pain (the majority of whom are on disability or other benefits) to pay their own way, or they do the right thing by the patient in front of them and either fudge the diagnosis or simply lie outright to obtain PBS approval for the drug.
Some ad hoc solutions exist around the country. The Department of Veterans Affairs as already mentioned has gabapentin and pregabalin available as Authority items.
Various employer insurance bodies and transport accident bodies are happy to pay for the drugs for their claimants if acceptable prescribing habits are followed.
It is the people who are not ‘lucky’ enough to suffer a compensable condition or find a GP willing to systematically exploit the PBS who miss out.
And now it seems the PBS is sending a clear signal that it intends to crack down on the prescribing of gabapentin, so the battle against a common and severe form of chronic pain will become harder to fight.”
• By way of declaration of interest I should mention that I have presented talks at educational meetings for GPs and other specialists for which I have received payment from companies including Mundipharma, Pfizer and Janssen-Cilag who all manufacture drugs related to pain management. I have not received research funding from industry. The details of these have all been declared to Medicines Australia as per the industry guidelines.
***
Dr John Dowden, Editor of Australian Prescriber, adds the following comment:
“Neuropathic pain is difficult to treat, partly because the drugs we have are not highly effective.
The current edition of Therapeutic Guidelines: Neurology does include some of the drugs mentioned by Dr Vagg as part of the management of patients with neuropathic pain. Both pregabalin and gabapentin have been approved by the Therapeutic Goods Administration for the treatment of neuropathic pain in Australia.
However, as Jon Hunt points out (in a comment on this post), only a minority of patients will benefit. It could be that this benefit was not large enough, when considered against the price of treatment, to show that the drugs were cost-effective for the Pharmaceutical Benefits Scheme (PBS). (This assumes that the manufacturer did actually apply to have the drugs included in the PBS for neuropathic pain).
I believe that gabapentin may now be off-patent, so the balance of cost and effectiveness could have changed.
If that is the case, then Dr Vagg could encourage the manufacturer to make a submission for the Pharmaceutical Benefits Advisory Committee to consider.“
• Declaration from Dr Dowden: I should point out that I am on the board of Therapeutic Guidelines, but I was not involved in writing the neurology guidelines.
This is not strictly correct: tricyclics have no PBS restrictions. However they are stupidly ancient medications with multiple problems including potentially fatal arrhythmias and have no advantage over duloxetine/venlafaxine.
I am not sure how being ancient also means stupid. It’s not their fault. From australian prescriber: “Clinical experience would suggest that antidepressants are often very helpful, especially in cases of peripheral neuropathic pain” “Evidence for the use of other antidepressants apart from tricyclics is very limited. Venlafaxine may be useful” and finally The number of patients who need to be treated with gabapentin for one to have a 50% reduction in pain has been calculated as five.
Ref: Aust Prescr 2006;29:72-5
But having said that I’m not sure what the therapeutic guidelines would suggest.
The generally accepted NNT for gabapentin, pregabalin and amitriptyline is 3.8, 4.2 and 2.9 respectively (Analgesic Guidelines revised edition July 2009). Quilici et al (BMC Neurol. 2009 Feb 10;9:6) concluded from their meta-analysis that gabapentin, pregabalin and duloxetine all had equivalent efficacy when compared from published trials.
Gabapentin has been off-patent for several years, but none of the generic manufacturers have applied for neuropathic pain approval, presumably as it was not given to the original Neurontin brand.
I think that for a complex and difficult diagnosis Dr Dowden would agree that even a minority of patients benefiting from appropriate treatment is better than none at all, which is the current situation.