How to help patients with neuropathic pain

Experts suggest that neuropathic pain will be more prevalent in the coming years due to post COVID-19 complications. It could also increase due to an aging and more obese population, bringing more cases of diabetic neuropathy, post herpetic neuralgia following shingles or nerve damage from herniated disks. Helping patients reduce their pain and improve their quality of life requires a trial-and-error approach to find the medication and dosing that balances effectiveness with side-effects. Guidance on how to do this comes from a consensus statement by the Canadian Pain Society on the pharmacological management of neuropathic pain. It was released in 2014, and re-published in Canadian Family Physician in 2017. Despite the guidelines being almost eight years old, the recommendations remain essentially the same, said Dr. Dwight Moulin, an author of the statement and professor in the departments of clinical neurological sciences and oncology at Western University in London, Ont. Read: Management of postherpetic neuralgia Dr. Moulin and Dr. Anuj Bhatia, associate professor at the University of Toronto and clinical director of acute and chronic pain services at Toronto Western Hospital, provided advice on how to help patients with neuropathic pain. 1. Set up realistic expectations about treatment Start a discussion about medication for neuropathic pain by validating the patient’s pain, Dr. Moulin said. Unlike some pain conditions, there’s usually an underlying cause, but patients have often dealt with the pain long before telling a physician. Next, set up realistic expectations about treatment. “The second thing I tell them is that right now we don’t have a cure for neuropathic pain because we don’t have a therapy that heals or reverses the injury. Our goal is to help make the pain tolerable, but we can’t get rid of it,” Dr. Moulin said. Dr. Bhatia said that the patient needs to understand that medication will require titration and the dosage increase will depend on the level of benefit and the severity of side-effects. Right now, there’s no way of predicting which medication or which dose will ease neuropathic pain in each patient. There must be active cooperation and communication on both sides of the therapeutic relationship to decipher the optimal treatment. Read: Tramadol will switch from prescription to controlled drug status in spring 2022 2. Assess which agent will work best for first-line therapy First-line therapy medications are gabapentinoids (e.g., gabapentin, pregabalin), tricyclic antidepressants (e.g., amitriptyline, nortriptyline) and serotonin-norepinephrine reuptake inhibitors (SNRIs) (e.g., duloxetine). There is little evidence supporting which agent is superior, and there are no robust head-to-head comparison trials, so physicians can choose which one is more suitable for their patient. “There are no right or wrong answers here,” Dr. Bhatia said. The preferred treatment is clear in cases of trigeminal neuralgia, where a sodium channel blocker such as carbamazepine should be used, Dr. Moulin said. For other cases of neuropathic pain, physicians may offer medications that they are comfortable prescribing. In some cases, there may be contraindications. For example, tricyclic antidepressants should be avoided in patients with an irregular heartbeat or problems with the prostate, Dr. Bhatia said. Read: Medical cannabis may have role in decreasing opioid use: study Comorbidities may influence what agent physicians choose to prescribe. People who have neuropathic pain and depression may benefit from a SNRI, Dr. Moulin said. The doses of tricyclic antidepressants used for pain are too low to affect depression. Patients with chronic anxiety and neuropathic pain may benefit from a gabapentinoid, which have been shown to reduce anxiety, Dr. Moulin said. How the pain presents may also provide clues on what first-line therapy to use. Some patients feel the pain more at night. Dr. Moulin said that a tricyclic antidepressant may help these patients sleep. “The most sedating is amitriptyline, but if that is not tolerated because of side-effects such as drowsiness during the day, dry mouth and constipation, nortriptyline could be used,” he said. Elderly patients may be at risk for falls with some first-line therapies. Topical lidocaine, a fourth-line treatment, may be an option for these patients. “There’s evidence that topical lidocaine, at 5% to 10% applied to the skin, can relieve local nerve injury pain. It’s the only agent of all of these that has negligible side-effects,” Dr. Moulin said. Read: Sexual dysfunction may persist after discontinuing SSRI or SNRI antidepressants Another factor to consider when prescribing is the cost of the medication. Many are not covered by provincial or territorial health plans, and filling prescriptions can cost $100 to $300 a month. 3. Find the balance between effect and side-effects Increasing the dose of a first-line therapy up to an effective level requires frequent contact with the patient. Dr. Bhatia has a pharmacist in his practice group who calls patients to follow up. He said that patients could also talk with their local pharmacist for guidance about dosing. Dr. Bhatia said he often writes the titration regimen right into the prescription. He said it is frustrating when a patient doesn’t progress to a higher dose. “A lot of times I find that patients who come to our clinic were started on a fairly low dose and nobody made the effort to actually increase the medication to see if it would work better,” he said. Unfortunately, most patients will experience side-effects with first-line therapy. The most common complaints are drowsiness, dry mouth and postural hypotension. “The good news is that these side effects usually get better as the patient gets more tolerant of the medications, after the first two or three weeks,” Dr. Bhatia said. “We advise patients to stay with the medication as long as they find the side-effects tolerable.” If side-effects are intolerable, switch agents or add another therapy. Read: Methadone as a pain treatment “For some patients with severe pain and multiple side-effects, we need to use multiple drugs together to bring the pain under control,” Dr. Moulin said. The drugs are added sequentially. “It’s trial and error with each drug,” he said. 4. Consider cannabinoids carefully The 2014 consensus statement includes cannabinoids as third-line therapy. The choice was controversial, since the International Association for the Study of Pain 2015 guidelines, published in the Lancet Neurology, did not recommend cannabinoids for the treatment of neuropathic pain. Although there’s an interest in prescribing cannabinoids to treat neuropathic pain, there’s a lack of evidence to support their use, Dr. Bhatia noted. Cannabinoids include a number of compounds, and patients are being prescribed all of them. “It is a bit like the wild west right now,” Dr. Bhatia said. He said when he asks patients what they are taking, “90% of our patients can’t even tell us what kind of cannabinoid they are taking,” Dr. Bhatia said. Prescriptions are often sent directly to the manufacturer or supplier and so the patient doesn’t know what their medication contains. Patients often think cannabinoids are natural and safe, but they are potent medications with possible adverse effects. “I’m all for exploring new treatments and being open to the possibility of benefit, but I find it quite concerning that we and our patients are essentially being exposed to these unregulated substances with no evidence guiding it, with the perception that these medicines are safe,” Dr. Bhatia said. Read: 5 Tips: Managing lower back pain A review and meta-analysis of randomized clinical trials of cannabinoids for chronic pain (including neuropathic pain) was published in the BMJ in September 2021. It suggested that cannabinoids provide a small to very small improvement in pain relief, physical functioning and sleep quality compared to placebo. 5. Include other therapies The Canadian Pain Society’s consensus statement states that treatment of neuropathic pain should include other healthcare professionals. Dr. Bhatia said that family physicians should try to connect their patients with a neurologist or a pain clinic because these patients often have complex needs. If the patient is stable, then they can be referred back to the family physician. Another point of frustration for Dr. Bhatia is that patients come to his specialty clinic quite late. “We know the longer that the level of pain stays, the harder it is to treat it,” he said. Other treatments for neuropathic pain have become more prominent, such as intravenous delivery of ketamine for patients with refractory pain. There is also more evidence supporting neuromodulation such as spinal cord stimulation or peripheral nerve stimulation as a treatment for neuropathic pain, Dr. Bhatia said. Read: Emgality (galcanezumab) now indicated to reduce cluster headache frequency There’s some thinking now that instead of trying patients on one medication after another, perhaps after a reasonable trial of one or two medications we should consider these more advanced therapies early on,” Dr. Bhatia said. To treat the whole patient, consider cognitive behavioural therapy. “The other thing that helps any kind of pain, including neuropathic pain, is psychological approaches,” Dr. Moulin said. While the problem of cost remains for one-to-one cognitive behavioural therapy, a number of online options are available. Dr. Moulin said that exercise is good for all kinds of pain, including neuropathic pain. Patients should exercise “whenever they can tolerate it—keep as active as possible,” he said.

How to help patients with neuropathic pain

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