What is the best course of treatment for a 42-year-old female patient with acute onset of severe lower back pain (lumbar pain) radiating down her right leg, exacerbated by standing, walking, and bending, who has not responded to acetaminophen (Tylenol) (paracetamol) and has no recent trauma or injury?

Treatment of Acute Lower Back Pain with Radiculopathy

Start NSAIDs immediately at full therapeutic doses as first-line treatment, add a skeletal muscle relaxant for short-term use given the severe pain and muscle tightness, advise the patient to remain active, and apply superficial heat for symptomatic relief. 1, 2

Immediate Pharmacologic Management

NSAIDs as Primary Treatment

• Prescribe naproxen 500 mg twice daily or ibuprofen 400-600 mg every 6-8 hours, as NSAIDs provide superior pain relief compared to acetaminophen and are the preferred first-line medication for acute low back pain with radicular symptoms. 1, 2, 3
• Use the lowest effective dose for the shortest duration necessary, with assessment of cardiovascular and gastrointestinal risk factors before prescribing. 2, 3
• Maximum daily dose for naproxen is 1250 mg on day one, then 1000 mg daily thereafter; for ibuprofen, maximum is 3200 mg daily. 3
• NSAIDs show small to moderate improvements in pain intensity and are more effective than acetaminophen, which showed no significant difference from placebo in acute low back pain. 2

Add Skeletal Muscle Relaxant

• Prescribe a skeletal muscle relaxant (cyclobenzaprine 5-10 mg three times daily, tizanidine 2-4 mg every 6-8 hours, or metaxalone 800 mg three to four times daily) for short-term use given the severe pain (9/10) and constant tightness. 1, 2
• Skeletal muscle relaxants improve short-term pain relief compared to placebo after 2 to 4 and 5 to 7 days in acute low back pain. 2
• All skeletal muscle relaxants cause central nervous system adverse effects, primarily sedation, so warn the patient about driving and operating machinery. 2
• Do not extend muscle relaxant use beyond 1-2 weeks, as there is no evidence supporting longer duration and sedation risks increase. 1

Essential Non-Pharmacologic Measures

Activity Modification

• Advise the patient to remain active and avoid bed rest, as activity restriction merely prolongs recovery and delays resumption of normal activities. 4, 1, 2
• Provide evidence-based reassurance about the expected favorable natural course of acute low back pain, as most patients experience substantial improvement in the first month. 4, 1
• Encourage continuation of daily activities within pain tolerance, as prolonged bed rest leads to deconditioning and worsens disability. 1, 2

Superficial Heat Application

• Apply superficial heat via heating pads or heated blankets for short-term symptomatic relief, with moderate benefit demonstrated at 5 days. 1, 2

Management of Radicular Symptoms

Consider Gabapentin for Radiculopathy

• If the radicular pain down the right leg persists beyond initial treatment, consider adding gabapentin starting at low doses (300 mg at bedtime, titrating to 300-600 mg three times daily) for neuropathic pain components. 4, 1
• Gabapentin provides small, short-term benefits for radiculopathy, though evidence specifically for lumbosacral radiculopathy is limited. 4, 1

When Initial Treatment Fails

Spinal Manipulation

• If the patient does not improve with medications and self-care after 1-2 weeks, consider referral for spinal manipulation by an appropriately trained provider (chiropractor, osteopath, or physical therapist), which provides small to moderate short-term benefits. 1, 2

Opioid Considerations

• Reserve opioid analgesics or tramadol only for severe, disabling pain not controlled with NSAIDs and muscle relaxants, given substantial risks including aberrant drug-related behaviors, abuse potential, and addiction. 2
• If opioids are necessary, prescribe for fixed, time-limited periods only. 2

Imaging Decisions

No Routine Imaging Initially

• Do not order imaging (X-ray, MRI, or CT) at this initial presentation, as routine imaging provides no clinical benefit in uncomplicated cases and leads to increased healthcare utilization without improving outcomes. 4, 1, 2
• Plain radiography and advanced imaging are not associated with improved patient outcomes and identify many radiographic abnormalities that are poorly correlated with symptoms but could lead to unnecessary interventions. 4

When to Order MRI

• Order MRI lumbar spine only if symptoms persist or progress despite 6 weeks of optimal conservative management, or if severe or progressive neurologic deficits develop (progressive weakness, bowel/bladder dysfunction, saddle anesthesia). 4, 1
• Prompt work-up with MRI is indicated if severe or progressive neurologic deficits develop or serious underlying conditions are suspected (vertebral infection, cauda equina syndrome, cancer with impending spinal cord compression), as delayed diagnosis and treatment are associated with poorer outcomes. 4

Follow-Up Strategy

Reassessment Timeline

• Reevaluate the patient in 1-2 weeks to assess response to treatment, as patients with acute low back pain generally experience substantial improvement in the first month. 4
• Earlier or more frequent reevaluation is appropriate given the severe pain (9/10) and radicular symptoms. 4
• If symptoms persist beyond 4-6 weeks despite optimal conservative management, consider MRI and referral to physical therapy for supervised exercise programs. 1

Critical Pitfalls to Avoid

• Do not prescribe systemic corticosteroids, as they are no more effective than placebo for acute low back pain with or without sciatica. 1, 2
• Do not recommend bed rest or activity restriction, as this provides no benefit and delays recovery. 1, 2
• Do not use extended courses of medications without clear evidence of continued benefits and absence of major adverse events. 1, 2
• Do not prescribe benzodiazepines, as they show similar effectiveness to skeletal muscle relaxants but carry higher risks for abuse, addiction, and tolerance. 2
• Monitor for hepatotoxicity if the patient continues acetaminophen at maximum doses alongside NSAIDs. 2