Neuropathic Pain 2

By Prof. Tissa Wijeratne and Prof. Robert D Helme

 

Treatment

     Neuropathic pain is challenging to manage, and many patients have pain that is refractory to currently available treatments for NP. In randomized trials (RCTs) that have studied drug therapy, between 2 and 8 patients need to be treated for one to achieve a 50% reduction in pain. 

     Dworkin and colleagues published a stepwise pharmacological approach in treatment of neuropathic pain.

     The first step is to establish a correct diagnosis of NP. Establishing the cause of the NP may lead to effective treatment of the cause, and identify related comorbidities.

     The second step is to initiate treatment of the NP with one or more of the following.

· Tricyclic antidepressant (eg. amitriptyline,  nortriptyline) or an SNRI (eg duloxetine, venlafaxine)

· Anti-epileptic drugs (eg. Gabapentin, pregabalin)

· Local anaesthetics (eg. topical and parenteral  lidocaine )

Strong, (eg. opioids) or weak analgesics (eg. tramadol)  alone or in combination with one the above; it should be noted that effective combination trials are rarely reported)

     The third step is to reassess the patients’ pain and quality of life. Continue the current treatment if there is a adequate analgesia (average pain reduced to 3/10 severity this is not a common measure of efficacy) with no major side effects. If average pain relief remains higher than 4/10 severity after an adequate trial add one of the other front line medication from the above. If there is no adequate pain relief after an adequate trial (average pain does not reduce to 3/10 severity) switch to an alternative frontline medication.

     Step four is to consider second or third line medication after trials with first line medications or a referral to a pain specialist/pain management centre.

     The European Federation of Neurological Societies (EFNS) have produced guidelines on pharmacological treatment of NP.  These guidelines were revised and republished in 2010. The EFNS guidelines classify the evidence of pharmacological treatment for commonly studied neuropathic pain conditions as follows:

 

Diabetic neuropathic pain

 Gabapentin, Pregabalin, TCA and Duloxetine recommended as first line treatment. Opioids and Tramadol recommended as second line treatment.

Trigeminal neuralgia

Carbamazepine and oxcarbazepine regarded as first line treatment. Surgery is the second line treatment. (Common practice now is to use a gabapentanoid after tegretol as they are quite useful)

Post Herpetic Neuralgia

Gabapentin, Pregabalin, TCA and Lidocaine (topical) regarded as first line treatment. Topical capsaicin and Opioids regarded as second line treatment.

 

Central Pain

Gabapentin, Pregabalin and TCA regarded as first line treatment. Cannabinoids (MS), Lamotrigine, Opiods and Tramadol regarded as second line treatment. (We believe the evidence for gabapentanoids is weak; TCA has strong evidence)

 

Summary

     It is intriguing to note that only a proportion of patients with lesions in the somatosensory system develop neuropathic pain. Age, gender, emotional and  cognitive features, pain intensity before and after the lesion may act as risk factors  and also demonstrate that there are other factors in addition to nerve lesions that contribute to the neuropathic pain[35]. For example, recent research in animal models points to the involvement of cytokines in the CNS in the pathogenesis of neuropathic pain with exciting possibilities for new effective treatments in selected cases. It is therefore becoming increasingly important to look at the mechanism of pain in each and every individual patient with a view to targeting individual patient specific, multi-disciplinary approaches to management of pain in order to alleviate the suffering of patients with neuropathic pain.

 

References

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Sri Lanka Association for the Study of Pain

The Sri Lankan Chapter of the International Association for the Study of Pain

© January 2014. Sri Lanka Association for the Study of Pain (SLASP). All Rights Reserved.

For Comments  ranjithwp@pdn.ac.lk

Workshops Held and

Local Coordinators

Resource Persons

Resource Materials

Þ Pain: An Overview

Þ Physiology of Pain

Þ Pharmacological Management of Pain

Þ Neuropathic Pain

Þ Abdominal Pain

Þ Orofacial Pain: An Overview

Þ Pain: Psychological Correlates

Þ Assessment of Pain

Þ Management of Acute Post-Surgical Pain

Þ Management of Pain in Obstetrics

Þ Management of Musculoskeletal Pain and Chronic Pain Syndromes

Þ Management of Pain in Children

Þ Management of Pain in Neonates

Þ Management of Acute Pain in Trauma

Þ Management of Cancer Pain

Þ Management of Headache

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