What is the best medication for a patient with lower back pain and a normal X-ray of the thoracolumbar spine, considering their medical history, including any history of gastrointestinal issues or kidney disease?

Best Medication for Lower Back Pain with Normal X-ray

For lower back pain with a normal thoracolumbar spine X-ray, NSAIDs are the first-line pharmacologic choice, with acetaminophen as an alternative if NSAIDs are contraindicated. 1, 2

First-Line Pharmacologic Options

NSAIDs provide moderate, clinically meaningful short-term pain relief and should be your initial medication choice. 3, 1, 2 The evidence supporting NSAIDs is stronger than for any other medication class, with good-quality data demonstrating effectiveness for both acute and chronic low back pain. 3

• Acetaminophen (up to 4g daily) is an appropriate alternative if NSAIDs are contraindicated due to gastrointestinal issues, kidney disease, or cardiovascular concerns. 1, 4 However, acetaminophen has less robust evidence for efficacy compared to NSAIDs. 3

When to Add Skeletal Muscle Relaxants

For acute low back pain (less than 4 weeks), add a skeletal muscle relaxant like cyclobenzaprine if NSAIDs alone provide inadequate relief. 3, 1

• Skeletal muscle relaxants have good evidence for effectiveness in acute low back pain specifically, but not for chronic pain. 3
• Start cyclobenzaprine 5 mg three times daily, as this dose demonstrates statistically significant superiority over placebo with fewer side effects than the 10 mg dose. 5
• Warning: Expect drowsiness and dry mouth as common side effects. 5 Use with caution in hepatic impairment, starting with 5 mg and titrating slowly. 5
• Limit use to 2-4 weeks maximum, as these medications are intended for short-term symptom control only. 3

Second-Line Options for Chronic Pain

If pain persists beyond 4 weeks and NSAIDs are insufficient or contraindicated:

• Duloxetine 60 mg daily is the preferred second-line agent for chronic low back pain. 2, 6 Start at 30 mg daily for one week to assess tolerability, then increase to the therapeutic dose of 60 mg daily. 6
• Duloxetine has moderate-quality evidence showing sustained effects beyond short-term use, unlike most other medications. 6
• Tramadol (25-50 mg every 6 hours as needed) can be added if duloxetine is inadequate after 4-6 weeks, but limit to 2-4 weeks maximum. 2, 6

Medications to Avoid

• Do NOT use systemic corticosteroids—they are ineffective for low back pain. 3, 2 Good evidence demonstrates no benefit over placebo. 3
• Avoid opioids for initial management due to abuse potential and only small benefit (approximately 1 point improvement on 0-10 pain scale). 1, 6 Reserve opioids only as a last resort after all other options have failed. 6
• Benzodiazepines have high sedation rates and should not be first-line choices. 3

Essential Non-Pharmacologic Therapies (Always Concurrent)

Medications alone are insufficient—always initiate non-pharmacologic treatments simultaneously. 1, 2, 6

• Advise patients to stay active and avoid bed rest, as maintaining activity reduces disability. 1, 7
• Apply superficial heat for short-term relief. 1, 7
• Refer to physical therapy with structured exercise programs, which have moderate-quality evidence for effectiveness. 1, 6
• Consider spinal manipulation, massage, or acupuncture as adjunctive therapies. 1, 6

Clinical Algorithm

1. Start NSAIDs (or acetaminophen if contraindicated) + non-pharmacologic therapies immediately. 1, 2
2. If acute pain (<4 weeks) and inadequate response: Add skeletal muscle relaxant for maximum 2-4 weeks. 3, 1
3. If pain persists beyond 4 weeks: Transition to duloxetine 30 mg daily × 1 week, then 60 mg daily. 2, 6
4. If still inadequate after 4-6 weeks on duloxetine: Add tramadol for maximum 2-4 weeks. 2, 6
5. Reassess at 2-4 weeks after any medication change, and discontinue all medications at 8-12 weeks to reassess need for continuation. 2, 6

Critical Monitoring Points

• Reassess pain intensity and functional status at 1 month; earlier if age >65, radiculopathy signs present, or worsening symptoms. 1
• Do not order repeat imaging unless red flags develop or symptoms persist beyond 4-6 weeks without improvement. 1, 2 A normal X-ray already excludes fracture and significant bony pathology. 1
• Monitor for NSAID gastrointestinal and renal toxicity, especially in patients with pre-existing kidney disease or GI issues. 3
• Most pharmacologic benefits are short-term only (<4 weeks), so avoid long-term medication use without clear ongoing benefit. 3, 2