Cyclobenzaprine Will Likely Provide Minimal Additional Benefit for Your Radicular Back Pain
Adding cyclobenzaprine (muscle relaxant) to your current regimen of naproxen, acetaminophen, and prednisone is unlikely to meaningfully improve your radiating leg pain and may only cause additional sedation without functional benefit.
Why This Recommendation
The Evidence Against Adding Cyclobenzaprine
The most recent high-quality evidence directly addresses your situation. A 2015 randomized trial in JAMA studied patients with acute low back pain and found no significant difference in functional outcomes between naproxen alone versus naproxen plus cyclobenzaprine at 1-week follow-up 1. The improvement in disability scores was essentially identical: 9.8 points with naproxen alone versus 10.1 points when cyclobenzaprine was added—a clinically meaningless difference of 0.3 points.
The Radicular Pain Problem
Your shooting pain down the leg to the knee suggests radiculopathy (nerve root involvement), not simple muscle spasm. This is a critical distinction because:
- Muscle relaxants work on muscle spasm, not nerve pain 2
- The 2017 American College of Physicians systematic review found insufficient evidence that muscle relaxants help radicular low back pain 2
- Evidence for radiculopathy treatment is "very limited" for muscle relaxants 2
What the Guidelines Actually Say
The 2007 ACP/APS guidelines found that skeletal muscle relaxants like cyclobenzaprine are effective for acute non-radicular low back pain only—providing moderate short-term pain relief for simple back strain 3. However, they explicitly state: "We could not draw definite conclusions about efficacy of other medications for sciatica or radiculopathy because few trials have specifically evaluated patients with this condition" 3.
The Side Effect Trade-Off
Cyclobenzaprine causes significant sedation without proven benefit in your situation 4. The FDA label confirms that combination therapy with naproxen "was associated with more side effects than therapy with naproxen alone, primarily in the form of drowsiness" 4. The 2007 systematic review found a 2.44-fold increased risk of central nervous system adverse events when adding muscle relaxants to NSAIDs 3.
What You're Already Taking Is More Appropriate
Your current regimen is actually better targeted:
- Naproxen (NSAID): Moderate evidence for small benefit in both acute and chronic low back pain, including some radicular presentations 2
- Prednisone (corticosteroid): While systemic corticosteroids show no benefit for pain in radiculopathy (moderate evidence), one recent trial showed small effects on function 2
- Acetaminophen: Though recent high-quality evidence shows it's ineffective for acute low back pain 2, it adds minimal risk
What Would Actually Help Radicular Pain
For shooting leg pain suggesting nerve involvement, the evidence supports:
- Gabapentin or pregabalin: Fair evidence for radiculopathy, though results are inconsistent 3
- Duloxetine (SNRI antidepressant): Moderate evidence for small but consistent benefit in chronic low back pain with neuropathic features 2
- Continuing your NSAID: Low-certainty evidence for small benefit in radicular pain 2
Common Pitfall to Avoid
Don't assume all back pain is muscle spasm. Radiating pain below the knee is a red flag for nerve root involvement, which requires different treatment than simple muscle strain. Cyclobenzaprine was designed for muscle spasm from local musculoskeletal injury, not nerve pain 4.
Bottom Line
The muscle relaxant will likely make you drowsy without improving your leg pain. If your symptoms persist beyond the short prednisone course, discuss gabapentin or duloxetine with your provider—these target nerve pain rather than muscle spasm and have actual evidence for radicular symptoms 3.