Pharmacotherapy for Treatment of Neuropathic Pain – Research Evidence

Just a short post this time around……

I realise this is not directly related to physiotherapy treatment but given that patients with a dominance of neuropathic pain and/or central sensitisation (e.g. those patients with a positive LANSS or DN4 score for neuropathic pain) would seem to be the more difficult ones to improve, I think it important we have some knowledge on the efficacy of medications used in the management of these patients.

See the following previous posts for information relating to diagnosing Neuropathic Pain.

The following articles briefly summarise the evidence base regarding use of pharmacotherapy for treatment of Neuropathic pain.

Chaparro et al (2012)

Systematic Review
Current mono therapy drugs are associated with limited efficacy and dose-related side effects.
This review evaluated the efficacy, tolerability and safety of various drug combinations for the treatment of neuropathic pain.
Multiple, good-quality studies demonstrate superior efficacy of two-drug combinations. However, the number of available studies for any one specific combination, as well as other study factors (e.g. limited trial size and duration), preclude the recommendation of any one specific drug combination for neuropathic pain.
In order to properly identify specific drug combinations which provide superior efficacy and/or safety, we recommend that future neuropathic pain studies of two-drug combinations include comparisons with placebo and both single-agent components.

Finnerup et al (2010)

Systematic Review
Randomized, double-blind, placebo-controlled trials on neuropathic pain treatment are accumulating, so an updated review of the available evidence is needed.
Tricyclic antidepressants, serotonin noradrenaline reuptake inhibitors, the anticonvulsants gabapentin and pregabalin, and opioids are the drug classes for which there is the best evidence for a clinical relevant effect.
Despite a 66% increase in published trials only a limited improvement of neuropathic pain treatment has been obtained.
A large proportion of neuropathic pain patients are left with insufficient pain relief.
Large-scale drug trials that aim to identify possible subgroups of patients who are likely to respond to specific drugs are needed to test the hypothesis that a mechanism-based classification may help improve treatment of the individual patients.

My Conclusions:

There are many other articles I could post about, but the overall consensus seems to be:

That pharmacotherapy for neuropathic pain has limited efficacy and dose related side effects i.e. most people don’t get great pain relief from them.
If patients do obtain benefit they often suffer significant side effects that may outweigh the benefits in pain reduction.

Having said all of the above, I still think that medications are worth a trial when patients have high pain levels and/or poor pain control as obviously pain can significantly interfere with any treatment approaches the patient may be undertaking.

References:

Chaparro LE, Wiffen PJ, Moore RA, Gilron I. Combination pharmacotherapy for the treatment of neuropathic pain in adults. Cochrane Database Syst Rev. 2012 Jul 11;7:CD008943.

Finnerup NB, Sindrup SH, Jensen TS. The evidence for pharmacological treatment of neuropathic pain. Pain. 2010 Sep;150(3):573-81.