World Health Organization essential medicines lists: where are the drugs to treat neuropathic pain?

Neuropathic pain is a priority health issue [5], which currently is the topic of the 2014–2015 Global Year Against Neuropathic Pain campaign of the International Association for the Study of Pain (http://www.iasp-pain.org/GlobalYear/NeuropathicPain). Between 6% and 10% of adults are affected by chronic pain with neuropathic features [6,14,25], and this prevalence is significantly greater among individuals with specific conditions. For example, neuropathic pain is a common comorbidity in infectious diseases such as HIV, leprosy, and herpes zoster, and in non-infectious conditions such as diabetes mellitus, stroke, multiple sclerosis, and traumatic limb and spinal cord injury [7,13,16,19,21]. The pain is associated with significant decreases in quality of life and socioeconomic well-being, even more so than non-neuropathic chronic pain [9,20,22]. Developing and emerging countries share the greatest burden of conditions that predispose to development of neuropathic pain [5,10], and can ill afford the negative consequences of this pain. There are medicines with proven efficacy in the treatment of neuropathic pain [11,12]. Nevertheless, the pain can be difficult to treat, with significant inter-individual variation in efficacy within and between drug classes, independent of the presumed aetiology of the neuropathy [2,4]. Effective management of neuropathic pain within a population therefore requires access to a small, but crucial group of drug classes with proven efficacy. The World Health Organization’s (WHO) model list of essential medicines (http://www.who.int/selection_medicines/list/en/) presents those medicines deemed necessary to meet priority health needs, and local implementation of essential medicines policies is associated with improved quality use of medicines [15,18]. But, none of the analgesic medicines included in the WHO model list are recommended as first-line treatments for neuropathic pain [11]. Thus the WHO model list is not a good framework from which national policies on managing neuropathic pain can be structured and countries routinely adapt the model list according to local needs and resources [18]. To estimate the nominal availability of medicines recommended for the treatment of neuropathic pain in developing and emerging countries, we assessed national essential medicines lists (NEMLs) for the inclusion of recommended treatments. We also assessed whether the coverage of recommended drugs classes on these NEMLs was dependent on countries’ economic status.