The Role of the Pharmacist in the Management of Chronic ...

C o n t i n u i n g E d u c a t i o n A l b e r t aTable 1: Selected conditions associatedwith neuropathic pain* 2,61,89Diabetic neuropathyPostherpetic neuralgiaHIV infectionTumour invasionRadiationChemotherapy-induced nerve damagePost-surgical nerve traumaPhantom limb painLumbar degenerative disc diseaseChronic low back painComplex regional pain syndromeTrigeminal neuralgiaVulvodyniaPost-stroke painMultiple sclerosisSpinal cord injury*NB: patients may also have neuropathic painwithout a diagnosed conditionskin (mechanical allodynia); burning whenthe skin is touched by something cold, oreven cool (thermal allodynia); pain thatlasts long after an initiating event (hyperpathia);an exaggerated response to painfulstimuli, such as a pin-prick (hyperalgesia);a difficult to describe, unusual or unpleasant“numbness” (dysesthesia); and tendernesswhen the area is touched gently.Additional symptoms may include fullor partial loss of sensation in the area ofpain (presumably from the initiating nervedamage), and pain that radiates to adjacent areas (i.e., not welllocalized). Unlike certain inflammatory conditions, neuropathicpain also tends to be asymmetrical.Neuropathic pain is classified as continuous, spontaneous orstimulus-evoked with “out of the blue” being a particularly tellingdescription. Other trigger words include cutting, prickling, throbbingor crushing, and shooting, stabbing, lancinating or jabbing. 2,7-22So how does one sort this out? Obviously the first step is tohave the patient see a doctor for diagnosis. Figure 1 (“About MyPain”) is an example of one tool that can facilitate communicationbetween the patient and his or her doctor about the possibility ofneuropathic pain. Designed for use through the pharmacist, it isbased on multiple validated pain questionnaires developed by painspecialists. 10-12,14-22 It is intended to help patients delineate their painsymptoms and history before they see the doctor, and in turn, helpsave physicians’ time while alerting them to the possibility of neuropathicpain. For expediency, as well as ease of use, only selectedsymptoms are included. Since these rarely occur in other pain conditions,the physician should be able to quickly identify potentialneuropathic pain, and follow up with further investigation.Two points are worth noting with respect to recognizing neuropathicpain. The first is that it always involves or requires morethan one word or characteristic. Secondly, the absence of an evenparticularly characteristic symptom does not necessarily precludethe presence of neuropathic pain. 9Figure 1: About my painThe following are some of the ways people describe pain from damaged nerves.This kind of pain is usually treated differently than “ordinary” or “normal” pain.To help your doctor know the best way to treat your pain, check as many spots as apply,and add any other words or symptoms that aren’t in the checklist.If you have pain in more than one place, use a separate form for each area.My Pain Is…oburningolike an electric shockotingling or pricklingonumb (or just feels abnormal)otender even when pressed gentlyoradiating (moving from its original spot)osensitive to light touch (such as a gentle breeze or loose clothing)Other ways I describe my pain are…__________________________________________________________________________________________________________________________________________Take this form to your doctor. The following are some questions he or she may ask.Think about these before you see your doctor so they are easier to answer “on the spot.”• Exactly where is the pain?• Is the pain always there, come and go, or seem to appear “out of the blue?”• How long have you had this pain?• What makes the pain worse?• What makes the pain better?• What medication(s) have you tried, and how much have they helped?• Besides medication, what else have you tried?Important: This form is not meant to diagnose any certain type of pain. Only yourdoctor is able to do this. If you or your doctor have any questions about this form, orabout pain medications, please feel free to contact your pharmacist.Pharmacy Contact InformationCopyright Brenda McBean Cochran; April 2009Pharmacological management of chronicneuropathic painChronic neuropathic pain has historically been treated the sameway as any chronic pain—ranging from simple analgesics to opiates.Growing recognition that neuropathic pain has quite differentpathophysiology than nociceptive pain prompted the CanadianPain Society to develop a 2007 consensus statement and guidelinesfor the pharmacological management of chronic neuropathicpain (hereafter referred to as the “Canadian Guidelines”). 2 Usingan evidence-based approach and recognizing that treatment mustbe individualized for each patient, tiered recommendations weremade for each class of medication used in chronic neuropathicpain. (Figure 2)Brief overview of neuropathic pain pathophysiologyAn appreciation of chronic neuropathic pain pathophysiology (atleast as far as we know it) can help pharmacists understand therationale for drug choices in this condition.Hyperactivity in both the central and peripheral nervous systemscontributes, through a variety of mechanisms, to neuropathicpain. Briefly, damaged nerves become highly sensitive to mechanicalstimulation and may also begin to generate impulses on their own(often referred to as “central” or “peripheral sensitization”). This increasedsensitivity and spontaneous activity appears to be due to increasedconcentration of sodium channels, as well as increased sen-CE 2June 2009 | pharmacy practice