Low Back Pain.pdf

3/19/24, 8:15 AM Low Back Pain Low Back Pain Kelly Grindrod, BSc(Pharm), PharmD, MSc Jason Kielly, BSc(Pharm), PharmD Carlo Marra, BSc(Pharm), PharmD, PhD, FCSHP Date of Revision: August 16, 2018 Peer Review Date: July 1, 2018 Pathophysiology Low back pain is defined as spinal and paraspinal symptom...

3/19/24, 8:15 AM Low Back Pain Low Back Pain Kelly Grindrod, BSc(Pharm), PharmD, MSc Jason Kielly, BSc(Pharm), PharmD Carlo Marra, BSc(Pharm), PharmD, PhD, FCSHP Date of Revision: August 16, 2018 Peer Review Date: July 1, 2018 Pathophysiology Low back pain is defined as spinal and paraspinal symptoms in the lumbosacral region that can extend to the gluteal muscles, hips and lower extremities.​ ​ With an estimated prevalence of 15–30%, between 50% and 80% of people will experience an episode of low back pain during their lifetime.​ Globally, low back pain causes more disability than any other disease, resulting in significant direct and indirect costs to the health-care system including direct medical care, disability, decreased productivity while at work and time lost from work.​ ​ Despite the high prevalence of disease, the incidence and prognosis of low back pain are difficult to characterize because of the variety of ways low back pain has been defined in studies.​ Historically, there has been a widely held belief that up to 90% of cases of low back pain will resolve within 2 months. Newer data indicate rapid improvement occurs within 6 weeks of presentation, after which the rate of improvement is slower.​ Up to 75% of people with low back pain will continue to have some degree of pain after 1 year.​ ​ Most will experience relapses in symptoms, and up to 10% of individuals experience chronic symptoms resulting in significant time away from work.​ ​ ​ ​ Factors that increase the risk of low back pain include age (most common between 45 and 64 years), greater height, climbing stairs often and stress.​ In addition, individuals who develop low back pain have a poorer prognosis if they have a higher level of disability, have sciatica, are older, or are in poor general health, have more stress in their lives, have poor relationships with work colleagues or have a heavy physical demand at work.​ ​ ​ Other factors that may be associated with low back pain include obesity​ and smoking.​ Usual daily activities that include frequent walking, standing, lifting or carrying have been associated with low back pain; however, evidence indicates these activities are not causative on their own.​ ​ ​ Low back pain can be acute (12 weeks' duration). Low back pain can be categorized as: 1) nonspecific low back pain; 2) low back pain associated with radiculopathy or spinal stenosis; or 3) low back pain associated with other specific spinal causes.​ In over 85% of people, the cause of low back pain cannot be reliably identified, though muscular-ligamentous injuries of the low back such as strains and sprains are often suspected.​ The symptoms, similar to those experienced with other muscle, ligament and tendon disorders, include localized pain of varying severity, spasm, inflammation and immobility. Radiculopathy results from the dysfunction of the nerve root.​ Symptoms include pain, sensory impairment, weakness and impaired tendon reflexes. Sciatica, which is the most common type of radiculopathy, is characterized by pain that radiates to the buttocks and down the posterior-lateral aspect of the leg. It may be described as a “shooting pain” originating in the lumbar region (location of the sciatic nerve). Other specific spinal causes can include cancer, vertebral compression fractures, spinal infections (e.g., herpes zoster), disc herniation, inflammatory spondyloarthritis (e.g., ankylosing spondylitis) and referred visceral pain (e.g., prostatitis, endometriosis, abdominal aortic aneurysm).​ Goals of Therapy Relieve symptoms https://cps-pharmacists-ca.login.ezproxy.library.ualberta.ca/print/new/documents/MA_CHAPTER/en/low_back_pain_minor 1/16 3/19/24, 8:15 AM Low Back Pain Maintain or improve mobility and quality of life Prevent or minimize re-injury Health-care practitioners can support the goals of therapy by educating patients and caregivers to help them understand the condition and make informed therapy decisions. Evidence suggests that patient education by primary care providers may reduce the number of primary care visits related to low back pain and provide long-term reassurance for patients with low back pain.​ Patient Assessment An algorithm for assessing patients with low back pain is presented in Figure 1. The most important aspect of assessing low back pain is ruling out potential “red flags” or serious etiologies that require immediate evaluation by an appropriate health-care practitioner, e.g., rapid weight loss, fever, neurologic deficit, inflammary disorder.​ Also, consider assessing patients for “yellow flags” or risk factors for developing chronic low back pain such as comorbid depression and anxiety (see Figure 1 for red flag and yellow flag symptoms requiring further assessment). Patients with chronic pain (lasting >12 weeks), sciatic conditions or specific causes for their pain also require further evaluation. Principles of Therapy The initial use of nonpharmacologic options for the management of low back pain is recommended. Pharmacologic therapy may be initiated if nonpharmacologic options fail to provide adequate relief and should always be used in combination with nonpharmacologic options. Numerous treatment approaches are supported by various levels of evidence of efficacy in the management of low back pain (see Table 1). Much of the available evidence lacks rigor with respect to study methodologies including sample size, randomization, use of placebo, blinding, and controlling for confounding variables and population variances (acute, chronic, ± sciatica). Current pharmacologic therapies for low back pain may provide symptomatic relief but are not curative. Evidence to support the use of pharmacologic agents is limited, and recommendations from published guidelines are mixed.​ ​ ​ Therefore, the choice of agent is based on a combination of risk versus benefit, cost and patient preference. If tolerated, pharmacologic therapies should be tried for at least 2–4 weeks to allow the patient to fully assess effectiveness while continuing with nonpharmacologic modalities. Nonpharmacologic Therapy In nonspecific low back pain, the primary recommendation is to provide patients with information and education on treatment options and the expected course of disease, and to advise them to maintain usual activity. Provide reassurance as acute or subacute low back pain improve over time regardless of treatment.​ ​ Advise individuals with low back pain to stay active and only avoid activities that may worsen pain or injury (e.g., heavy lifting, twisting, high impact exercise). Although bed rest was historically recommended, staying active may offer patients better pain relief and function.​ The combination of education and exercise may offer some short-term benefit.​ If possible, patients should be assessed by a physiotherapist to identify appropriate exercise intensity.​ Table 1: Conservative Treatments for Low Back Pain Acute (4 wk) Category Treatment Pharmacologic Therapy NSAIDs Muscle relaxants https://cps-pharmacists-ca.login.ezproxy.library.ualberta.ca/print/new/documents/MA_CHAPTER/en/low_back_pain_minor 2/16 3/19/24, 8:15 AM Category Nonpharmacologic Therapy Low Back Pain Treatment Acute (4 wk) Duloxetine Opioids, tramadol Reassure and promote self-care (provide books, handouts and advice to remain active) Acupuncture Application of superficial heat Massage Spinal manipulation​[a] Exercise Low level laser therapy​[a] Motor control exercise​[a] Multidisciplinary rehabilitation Psychotherapeutic approaches​[b] (cognitive behavioural therapy, electromyography biofeedback, mindfulness-based stress reduction, operant therapy, progressive relaxation) Tai chi​[a] Yoga​[a] [a] Low-quality evidence; recommendations are based on lack of harms and small to moderate effect on either pain and/or function. [b] Recommendation for mindfulness-based stress reduction is based on moderate-quality evidence suggesting improvement in pain and function; other recommendations are based on low-quality evidence, lack of harms and small to moderate effect on either pain and/or function. Adapted with permission from Qaseem A, Wilt TJ, McLean RM et al. Noninvasive treatments for acute, subacute, and chronic low back pain: a clinical practice guideline from the American College of Physicians. Ann Intern Med 2017;166(7):514-30. Copyright © 2017 American College of Physicians. All Rights Reserved. Reprinted with the permission of American College of Physicians, Inc. Other nonpharmacologic therapy including massage therapy may provide a small benefit in acute or subacute low back pain but does not provide functional improvement in chronic low back pain.​ Fair-quality evidence suggests that acupuncture may be safe and effective in improving pain and function at the end of treatment for chronic low back pain.​ Spinal manipulation may have a small effect on function in acute low back pain and may improve both pain and function in chronic low back pain but further quality trials are required.​ Motor control exercises, which include back exercises aimed at restoring coordination, strength and control, may improve pain or function in patients with subacute https://cps-pharmacists-ca.login.ezproxy.library.ualberta.ca/print/new/documents/MA_CHAPTER/en/low_back_pain_minor 3/16 3/19/24, 8:15 AM Low Back Pain or chronic symptoms but not in acute nonspecific low back pain.​ Low-level laser may reduce pain for up to 3 months when used on its own or in combination with other treatments, but further trials with patient blinding are required.​ In chronic nonspecific low back pain, general exercise programs are at least as effective as other conservative treatments such as the provision of self-care education books, massage, spinal manipulation and back schools (structured programs where individuals are taught how to maximize recovery and minimize recurrences of low back pain).​ ​ ​ Certain post-treatment exercise programs may prevent the recurrence of low back pain.​ Yoga, tai chi and stretching may improve both pain and function in chronic low back pain,​ ​ while Pilates shows only small or no clear effects on pain or function.​ The application of heat may provide short-term relief in acute pain but there is insufficient evidence to recommend the use of cold packs.​ Other modalities such as therapeutic ultrasound,​ lumbar supports, corsets, shoe lifts, insoles and orthoses​ have shown little benefit. Evidence suggests that psychotherapeutic or behavioural approaches such as cognitive behavioural therapy, operant therapy, progressive relaxation or electromyography biofeedback may result in lower post-treatment pain intensity.​​ Mindfulness-based stress reduction may provide a greater improvement in pain symptoms and function compared to the usual treatment at 26 weeks.​​ The combination of behavioural therapy and exercise may decrease disability and pain and improve quality of life compared with exercise alone.​ A number of reviews suggests that a multidisciplinary biopsychosocial treatment approach may result in larger improvements in pain and daily function compared with usual care or interventions aimed only at physical factors.​ ​ ​ Behavioural therapy for chronic low back pain should be incorporated on an individual basis and under the care of a qualified professional. Surgical therapy is considered in individuals with persistent and disabling symptoms from common degenerative spinal changes or spinal stenosis, or in individuals with disabling radiculopathy from a herniated disk.​ Pharmacologic Therapy For further discussion of pharmacologic therapy for low back pain, consult the Compendium of Therapeutic Choices: Low Back Pain. For comparative ingredients of nonprescription products, consult the Compendium of Products for Minor Ailments— Analgesic Products: Internal Analgesics and Antipyretics; Herbal and Natural Health Products: Single Entity. Medication is commonly prescribed for nonspecific low back pain but is primarily intended to relieve pain and discomfort in the short term and to facilitate activity. Long-term therapy may be required in individuals who experience chronic back pain. Common treatments for nonspecific low back pain include acetaminophen, NSAIDs, opioid analgesics, skeletal muscle relaxants and antidepressants. Evidence of efficacy for all agents is generally weak.​ Table 3 presents selected pharmacologic options for the treatment of low back pain. Acetaminophen has long been the first-line agent to treat low back pain, but evidence suggests that acetaminophen may be ineffective for this condition and have greater risks than previously thought.​ ​ Guidelines no longer recommend acetaminophen for management of acute or chronic low back pain.​ ​ Small trials have suggested that acetaminophen does not provide superior pain relief compared with NSAIDs.​ ​ A small randomized controlled trial found that continuous heat wrap therapy may provide better pain relief than regular doses of acetaminophen or ibuprofen.​ Patients taking acetaminophen should be counselled not to exceed the daily maximum dose and to consider acetaminophen from all sources (nonprescription and prescription). NSAIDs are the only pharmacologic option endorsed by current guidelines.​ ​ ​ They may provide small improvements in low back pain in patients without sciatica compared with placebo, while in patients with sciatica, pain reduction may not be significant. There is no demonstrated superiority of one NSAID over another.​ ​ Combination products containing acetaminophen, caffeine and codeine (8 mg) have not demonstrated benefit in the management of acute or chronic nonspecific low back pain. https://cps-pharmacists-ca.login.ezproxy.library.ualberta.ca/print/new/documents/MA_CHAPTER/en/low_back_pain_minor 4/16 3/19/24, 8:15 AM Low Back Pain With low back pain, as with other muscular strain disorders, the complexity of spasm physiology makes it difficult to determine the extent to which spasm is contributing to the injury or symptoms. Evidence to support the use of muscle relaxants for low back pain is unclear.​ While some studies have suggested benefit when used as monotherapy or in combination with other agents,​ ​ some studies have suggested limited benefit over use of NSAIDs alone.​ ​ If patients have contraindications to analgesics, have failed all other treatments or have been diagnosed with a spastic component to their disease, direct-acting muscle relaxants (baclofen, benzodiazepines, cyclobenzaprine and tizanidine) may be used. Nonprescription muscle relaxants such as chlorzoxazone, methocarbamol or orphenadrine have little direct muscle-relaxing properties or evidence to support their use.​ Muscle relaxants are associated with an increased risk of adverse effects, such as dizziness, drowsiness and sedation, which outweigh their benefits. If used at all, they should be used with caution, particularly in elderly patients.​ Current guidelines differ regarding the use of opioids for acute and chronic low back pain.​ ​ Small trials comparing opioid analgesics with NSAIDs report conflicting results; opioids may be reserved for individuals with persistent lowback pain who have not responded to other therapies.​ ​ A systematic review suggests there is insufficient evidence to determine the effectiveness of long-term opioid therapy in improving chronic pain and function.​ There is evidence of short-term efficacy (moderate for pain and small for function) of opioids to treat chronic low back pain compared with placebo. However, the effectiveness and safety of long-term opioid therapy for treatment of chronic low back pain remains unproven.​ Canadian guidelines for the use of opioids to manage chronic non-cancer pain recommend a trial addition of opioids to current therapy only when nonpharmacologic and pharmacologic options have been optimized. Opioids should be discontinued if important improvements in pain and function have not been achieved in 3–6 months.​ A systematic review of opioids in chronic low back pain showed tramadol had a small effect on pain but was also associated with significant side effects such as headache, nausea, somnolence and constipation. Tramadol is not routinely used to treat low back pain as adverse effects limit its use in many patients.​ Natural Health Products There have been numerous claims that agents such as D-phenylalanine, devil's claw, capsicum, ginger, turmeric and white willow bark are effective in managing symptoms of low back pain. A Cochrane review of natural health products for nonspecific low back pain found that low- to moderate-quality evidence suggests that 4 herbal medicines (devil’s claw, white willow bark, cayenne and comfrey root extract) may reduce pain in acute and chronic lower back pain.​ For devil's claw, standardized daily doses of 50–100 mg of the active ingredient harpagoside improved pain compared with placebo. White willow bark, in standardized daily doses of 120–240 mg of the active ingredient salicin provided similar benefit. Topically applied cayenne and comfrey appear to reduce pain more than placebo. These topical agents could be considered as a treatment option for acute (comfrey) and for chronic (cayenne) low back pain. There is no evidence that any of these substances are safe or efficacious for long-term use.​ Note that the quantity of active ingredient was standardized for these studies and this cannot be expected with all products currently available in Canada. Monitoring of Therapy Table 2 provides a monitoring plan for patients with low back pain. Table 2: Monitoring of Therapy for Low Back Pain Parameter Degree Time frame Action/Comments Pain relief Elimination of pain or progression toward predefined goals as set by patient at the Patient or caregiver: assess daily Patient requires further assessment by appropriate health-care practitioner if symptoms not relieved after adequate trial of at least 2 analgesics or if new or worsening pain symptoms develop during therapy. Health-care practitioner: call on days 3, 7, 14 and 28 Use visual analog scale or other individual measure (e.g., ability to https://cps-pharmacists-ca.login.ezproxy.library.ualberta.ca/print/new/documents/MA_CHAPTER/en/low_back_pain_minor 5/16 3/19/24, 8:15 AM Parameter Low Back Pain Degree Time frame beginning of therapy Action/Comments perform ADLs—walking, gardening) to quantify and characterize pain. Trial of each analgesic for 2–4 wk at optimal dose to fully assess impact on daily activities/functioning. Considerations in timing of medications: Around-the-clock vs. PRN Take dose of analgesic at least 1 h prior to activities that may exacerbate pain. Nausea, dyspepsia, abdominal discomfort Minimal or none during therapy Patient or caregiver: monitor daily Health-care practitioner: call on days 3 and 7 (NSAIDs) Hematemesis, melena, hematochezia None during therapy (NSAIDs) Hypertension (NSAIDs) Renal function and signs of fluid retention (weight gain or edema) in high-risk patients Patient or caregiver: monitor daily on an ongoing basis Health-care practitioner: call on days 3, 7 and 28, then ask when medication is refilled Change therapy if symptoms severe or intolerable. Minimize development by taking medication with food or milk. Consider antacids or H2RAs for short-term treatment of dyspepsia. Assess risk of GI complications (see Compendium of Therapeutic Choices: Osteoarthritis, Table 1 for risk factors of serious adverse effects with NSAID therapy). If high risk, patient requires further assessment by appropriate health-care practitioner. Patient should discontinue therapy immediately and seek medical attention if these signs or symptoms develop. Stable during therapy Health-care practitioner: measure BP within 1 wk of starting NSAIDs Monitor patients with pre-existing hypertension; if BP increases, adjust the dose of the NSAID or that of the antihypertensive. No significant change in renal function Patient or caregiver: look for decreased urine production; watch for signs of fluid retention on an ongoing basis, (e.g., edema). Patients with severe heart failure should weigh themselves daily. Assess risk of renal complications (see Osteoarthritis, Table 3 for risk factors of serious adverse effects with NSAID therapy). Hold NSAID that day if patient cannot eat or drink. (NSAIDs) Discontinue NSAID if significant changes in serum creatinine, electrolytes or signs of fluid retention occur. Health-care practitioner: in patients >65 y or with other risk factors, consider baseline serum creatinine, repeat at 1 wk and then periodically afterwards. Recurrent low back injury Avoid or minimize Patient: ongoing Patient to seek medical attention if recurrent episodes occur, to identify and implement potential nonpharmacologic strategies for management and prevention. https://cps-pharmacists-ca.login.ezproxy.library.ualberta.ca/print/new/documents/MA_CHAPTER/en/low_back_pain_minor 6/16 3/19/24, 8:15 AM Low Back Pain Parameter Degree Time frame Action/Comments Functional ability after acute injury Avoid immobilization. Patient able to perform ADLs, usual activity to tolerable pain level Patient: daily Further assessment by appropriate healthcare practitioner required if unable to perform ADL. Health-care practitioner: call on days 3 and 7 Abbreviations: ADL = activities of daily living; BP = blood pressure; H2RA = H2-receptor antagonist Advice for the Patient Advise patients on: The importance of using nonpharmacologic measures concurrently with medication The importance of maintaining ordinary activities and increasing level of activity based on pain tolerance Expected benefits of treatment Possible side effects (see Table 3) and their management When to contact a health-care practitioner Algorithms Figure 1: Assessment of Patients with Low Back Pain https://cps-pharmacists-ca.login.ezproxy.library.ualberta.ca/print/new/documents/MA_CHAPTER/en/low_back_pain_minor 7/16 3/19/24, 8:15 AM Low Back Pain [a] Cauda equina syndrome: a rare clinical syndrome characterized by dull pain in the lower back and upper buttock region, and analgesia in the buttocks, genitalia or thigh, accompanied by a disturbance of bowel and bladder function. Drug Table Table 3: Drug Therapy for Low Back Pain https://cps-pharmacists-ca.login.ezproxy.library.ualberta.ca/print/new/documents/MA_CHAPTER/en/low_back_pain_minor 8/16 3/19/24, 8:15 AM Drug/​Cost[a] Low Back Pain Dosage Adverse Effects Drug Interactions Comments Hepatotoxicity: increased risk in malnourished patients, those with excessive alcohol intake (e.g., >3 drinks/day) or pre-existing hepatic disease; perform baseline LFTs in high-risk patients. Acetaminophen has been reported to increase INR in warfarin-treated patients. Check INR if acetaminophen ≥2 g/day is used for ≥3 consecutive days. Adjust warfarin dosage as required. Phenytoin, barbiturates, carbamazepine may increase acetaminophen metabolism and formation of toxic metabolite; thus, increased risk of hepatotoxicity. Risk may be increased in patients taking high therapeutic doses of acetaminophen and antiepileptic drugs chronically. Maximal onset of pain relief: within 24–48 h. Lower doses may be required in patients with severe hepatic and renal disease. Acetaminophen has been reported to increase INR in warfarin-treated patients. Check INR if acetaminophen ≥2 g/day is used for ≥3 consecutive days. Adjust warfarin dosage as required. Phenytoin, barbiturates, carbamazepine may increase acetaminophen metabolism and formation of toxic metabolite; thus, increased risk of hepatotoxicity. Risk may be Maximal onset of pain relief: within 24–48 h. Lower doses may be required in patients with severe hepatic and renal disease. Drug Class: Analgesics, oral acetaminophen Atasol Preparations, Tylenol, generics 325–1000 mg Q4–6H PO SR: 650 mg Q8H PO (maximum 4 g/day)