Tingling. Burning. Shooting. Stabbing. If you suffer from neuropathic pain, these unfortunate adjectives are all too familiar.

Neuropathic pain, or neuropathy, is a catch-all term for pain caused by damage to the nervous system. It’s one of the most common forms of chronic pain, affecting one to two per cent of the population and producing feelings of weakness, numbness, tingling and burning.

“Neuropathic pain is something we see a lot in our older patients,” says Natural Care’s Director of Patient Care, Karen Newell, who is also a registered practical nurse. “It’s fairly common in seniors because they are likely to be dealing with one or more of the conditions that cause it.”

What causes neuropathic pain?

Neuropathy has many causes, including:

• Alcoholism
• Autoimmune diseases (including diabetes, multiple sclerosis, lupus, rheumatoid arthritis and thyroid disorders)
• Chemotherapy treatment
• Exposure to toxins
• Fibromyalgia
• HIV
• Injuries
• Shingles
• Surgery

How long does neuropathic pain last?

Neuropathic pain can come and go over the course of a day, or even come and go over weeks and months. There’s no one set path for the journey through neuropathic pain. For most, it’s a chronic companion, for some, it’s a temporary travelling partner who can be kicked to the curb.

Can cannabis help neuropathic pain?

Anecdotally, several of our patients report that cannabis helps with their neuropathic pain, but so far the evidence is mixed.

A review published in the AMA Journal of Ethics concluded that cannabis is comparably effective to the traditional agents used to treat neuropathic pain. The review looked at studies conducted with vaporized or smoked cannabis flower of low to medium THC concentration (two to nine per cent). Study subjects ranged from HIV patients dealing with neuropathy to healthy volunteers who had been  purposefully injected with pain-inducing capsaicin (the ingredient that makes peppers hot).

Another review, which looked at studies conducted with a range of cannabis products – from synthetic cannabinoids, to sprays containing a mix of THC and CBD, to inhaled flower and more found “no high-quality evidence” to support the use of cannabis for neuropathic pain, citing side effects of sleepiness, dizziness and mental problems compared with placebo.

These reviews are interesting because they both draw their conclusions from a mixed bag of studies, often featuring multiple and diverse cannabis products used to treat neuropathy of multiple and diverse origins. Imagine a sommelier saying “wine never pairs with meat” or “wine always pairs with meat” and you can easily understand the problem we face in interpreting these kind of broad reviews.

Determining the right cannabis product for a specific health goal is more complicated than choosing the right wine for dinner: cannabis comes in many different strains, strengths and formats (vaporized, ingested capsules and oils, etc), and every person processes it differently, making it difficult to generate conclusive prescriptions.

Interestingly, smaller studies looking at specific products and dosages tend to generate more promising results:

A 2013 double-blind, placebo-controlled study published in the Journal of Pain found that low-dose cannabis (1.29 per cent THC or less) significantly improved neuropathic pain when compared with medium-dose and placebo cannabis. Most of the subjects in this study had already experienced poor results with conventional neuropathic pain treatments, leading its authors to conclude that “vaporized cannabis, even at low doses, may present an effective option for patients with treatment-resistant neuropathic pain.”

Similarly, a 2010 trial published in the Canadian Medical Association Journal looked at 23 patients who were assigned three different strengths of cannabis to manage post-traumatic and post-surgical neuropathic pain. The conclusion? “A single inhalation of 25 mg of 9.4% tetrahydrocannabinol herbal cannabis three times daily for five days reduced the intensity of pain, improved sleep and was well tolerated. Further long-term safety and efficacy studies are indicated.”

Cannabis Pharmacy author Michael Backes writes that this study is particularly significant because the best results were observed at the lowest dose, highlighting “the unexpected medical effectiveness of cannabis dosages that are far below those commonly consumed within the medical community.”

Finding the right product and dose for your neuropathic pain

Backes suggests that a variety of cannabis products, from topicals to oils to flower, may help a variety of neuropathy-related symptoms.

Natural Care nurse practitioner Lynn Haslam says she typically starts neuropathic pain patients on a low nighttime dose of a balanced CBD to THC oil. “We really want the pain managed so they can sleep,” she says. “Neuropathic pain typically gets worse at night, electric shock-like. We may not be able to diminish all of these sensations, but if we can restore sleep, which will help decrease pain during the day, that may be a reasonable goal.”

Setting realistic goals and weighing risks versus benefits is important when working with any medication, adds Haslam. “First-line therapy for neuropathic pain can be nortriptyline or amitriptyline,” she says, “and these medications can cause issues with older adults. This is the same with the other medications commonly used – gabapentin or pregabalin. I think cannabis is usually worth trying.”

In the absence of research that conclusively says which dose and product will work for which type of patient, Natural Care takes a conservative, personalized approach.

“Of course, we follow the latest cannabis research with great interest,” says Newell. “The more studies the better. But on a day to day basis, we weigh potential risks and benefits in a highly individual way – what medications is the patient taking? Are they at risk for drug interactions or falls? Have they had good or bad experiences with cannabis already? What is the nature of their pain, and have they tried other treatments? Then we start at the lowest dose possible and see if it helps. For many of our neuropathic pain patients, that’s enough.”