Medications for Acute Back Pain in the Emergency Room
For acute back pain in the emergency room, NSAIDs should be used as first-line treatment, with muscle relaxants as adjunctive therapy, while opioids should be reserved only for severe pain that doesn't respond to other treatments and prescribed at the lowest effective dose for a limited duration. 1
First-Line Treatment Options
NSAIDs
- Ibuprofen: 400-800 mg orally every 6-8 hours (maximum 3200 mg/day) 2, 1
- Naproxen: 500 mg initially, then 250 mg every 6-8 hours 3, 1
- Ketorolac: Can be considered for severe pain; provides comparable analgesia to acetaminophen-codeine with fewer adverse effects 4
NSAIDs provide small but clinically significant improvement in pain intensity compared to placebo for acute low back pain (moderate-quality evidence) 1. They work by inhibiting cyclooxygenase enzymes, reducing inflammation and pain.
Muscle Relaxants
- Cyclobenzaprine: Start with 5 mg three times daily, especially in elderly patients or those with hepatic impairment; can increase to 10 mg three times daily if needed 5
Skeletal muscle relaxants provide improved short-term pain relief compared to placebo after 2-7 days for acute low back pain (moderate-quality evidence) 1. They are particularly useful when muscle spasm is present.
Second-Line/Adjunctive Options
Acetaminophen
- Can be used in combination with other medications
- Note: As monotherapy, acetaminophen has low-quality evidence showing no difference in pain intensity compared to placebo 1, 6
Combination Therapy
- Naproxen + Cyclobenzaprine: A 2015 study showed that adding cyclobenzaprine to naproxen did not significantly improve functional outcomes compared to naproxen alone 7
For Severe Pain Only
Opioid Options (use with caution)
- Hydrocodone/Acetaminophen: 5-15 mg hydrocodone component every 4-6 hours PRN 3
- Oxycodone/Acetaminophen: 5-15 mg oxycodone component every 4-6 hours PRN 3
A 2015 randomized clinical trial found that adding oxycodone/acetaminophen to naproxen did not improve functional outcomes compared to naproxen alone for acute low back pain 7. Therefore, opioids should be reserved for cases where other options have failed.
Treatment Algorithm
Start with NSAIDs:
- Ibuprofen 800 mg orally every 8 hours OR
- Naproxen 500 mg initially, then 250 mg every 6-8 hours
Add muscle relaxant if muscle spasm is present:
- Cyclobenzaprine 5-10 mg three times daily
For severe, refractory pain only:
- Consider short-term opioid (lowest effective dose for ≤1 week)
- Prescribe with clear instructions and assessment of risk for misuse 3
Important Considerations
Safety Precautions
- NSAIDs: Use with caution in patients with history of GI bleeding, cardiovascular disease, or chronic renal disease 8
- Muscle Relaxants: May cause drowsiness; advise patients about driving and operating machinery 5
- Opioids: If prescribed, use the lowest practical dose for a limited duration (e.g., 1 week) 3
Common Pitfalls to Avoid
Overreliance on opioids: The American College of Physicians recommends opioids only for severe, disabling pain that is not controlled with NSAIDs 1
Prolonged bed rest: Advise patients to continue normal daily activities as much as pain allows 1
Routine imaging: Not recommended for nonspecific low back pain as it doesn't improve outcomes 1
Overlooking non-pharmacological options: Heat application has good evidence for moderate benefits in acute pain 1
Acetaminophen monotherapy: Recent evidence suggests limited efficacy for acute low back pain 6
Follow-up Recommendations
- Advise patients to follow up if pain persists beyond 1-2 weeks
- Consider referral to physical therapy if symptoms persist beyond 4 weeks 1
- Screen for red flags that might indicate serious underlying pathology requiring further evaluation
By following this evidence-based approach, emergency physicians can effectively manage acute back pain while minimizing risks associated with medication use, particularly opioids.