Back Pain: Drugs That Cause It and Drugs That Treat It

Medications That Treat Back Pain

First-line pharmacotherapy for acute low back pain centers on nonsteroidal anti-inflammatory drugs. A 2008 Cochrane systematic review of 65 trials (N=11,237) found that NSAIDs were more effective than placebo for short-term pain relief and global improvement in patients with acute and chronic low back pain [1]. Naproxen 500 mg twice daily and ibuprofen 400-800 mg three times daily are the most commonly studied regimens.

The choice among NSAIDs matters less than the decision to use one at all. Head-to-head comparisons show no consistent superiority of one NSAID over another for back pain [1]. Gastrointestinal and cardiovascular risks guide selection: patients over 65 or those with peptic ulcer history should receive a proton pump inhibitor alongside the NSAID or switch to a COX-2 selective agent like celecoxib. The American College of Physicians (ACP) 2017 guideline on noninvasive treatments for low back pain recommends NSAIDs as first-line pharmacotherapy for acute or subacute low back pain [2].

Skeletal muscle relaxants, including cyclobenzaprine 5-10 mg at bedtime, tizanidine, and methocarbamol, provide modest additional benefit when combined with NSAIDs in the first two weeks of an acute episode. A systematic review published in the Annals of Internal Medicine found moderate-quality evidence that muscle relaxants relieve acute low back pain in the short term, though sedation is common and limits daytime use [3]. These drugs should not be prescribed beyond two to four weeks.

Duloxetine and Antidepressants for Chronic Back Pain

Duloxetine (Cymbalta) at 60 mg/day is FDA-approved for chronic musculoskeletal pain, including chronic low back pain. Two randomized controlled trials (HMEF and HMEH, combined N=401 and N=236) demonstrated that duloxetine 60 mg/day reduced weekly mean pain scores by approximately 1.5 points on an 11-point numeric rating scale compared with placebo over 13 weeks [4]. The number needed to treat (NNT) for 30% pain reduction was approximately 6.

Dr. Roger Chou, lead author of the ACP low back pain guideline, has stated: "For patients with chronic low back pain, duloxetine is one of the pharmacologic options with adequate evidence of benefit, and clinicians should consider it particularly when NSAIDs are contraindicated" [2]. Tricyclic antidepressants like amitriptyline have been used off-label for decades, but the evidence base for low back pain specifically remains thin and inconsistent.

Gabapentinoids (gabapentin and pregabalin) are frequently prescribed for back pain with a radicular component. A 2017 NEJM trial (N=209) found that pregabalin did not significantly reduce leg pain intensity in patients with sciatica compared with placebo over 52 weeks, with the adjusted mean difference being only -0.5 on a 10-point scale (95% CI, -1.2 to 0.2) [5]. This trial challenged a widespread off-label practice.

Acetaminophen: Less Effective Than You Think

Many patients and clinicians assume acetaminophen (paracetamol) is a reliable option for back pain. It is not. The PACE trial, a landmark randomized controlled trial published in The Lancet in 2014 (N=1,652), compared acetaminophen at regular doses (up to 4 g/day), as-needed doses, and placebo for acute low back pain [6]. Median time to recovery was 17 days in all three groups. There was no difference.

The ACP 2017 guideline explicitly recommends against acetaminophen as monotherapy for acute low back pain based on this evidence [2]. The drug may still have a role as an adjunct or for patients who cannot tolerate NSAIDs, but it should not be the sole pharmacologic intervention.

Opioids: Evidence Does Not Support Routine Use

Opioids remain widely prescribed for back pain in the United States despite accumulating evidence against their routine use. A 2018 JAMA trial (the SPACE trial, N=240) compared opioid therapy with non-opioid medications for chronic back pain and hip or knee osteoarthritis over 12 months [7]. Pain-related function at 12 months was not significantly different between the opioid and non-opioid groups, but the opioid group experienced significantly more medication-related adverse effects.

The ACP guideline positions opioids as a last resort for chronic low back pain, to be considered only when first-line therapies (NSAIDs, duloxetine, nonpharmacologic therapies) have failed and only after a discussion of known risks and realistic benefits with the patient [2]. Dr. Atul Deyo, a back pain researcher at Oregon Health & Science University, noted: "The evidence simply does not support opioids as a long-term strategy for chronic back pain. The risks of dependence, tolerance, and hyperalgesia outweigh the modest short-term analgesic benefit for most patients" [8].

Short courses of tramadol or low-dose opioids (oxycodone 5 mg every 6 hours) may be appropriate for severe acute pain unresponsive to NSAIDs and muscle relaxants, but these should not extend beyond seven days without reassessment.

Systemic Corticosteroids for Acute Radiculopathy

Oral prednisone and methylprednisolone dose packs are frequently prescribed for acute lumbar radiculopathy (sciatica), but the evidence is mixed. A 2015 JAMA trial (N=269) compared a 15-day tapering course of oral prednisone with placebo for acute sciatica [9]. The prednisone group showed a modest improvement in disability scores at 3 weeks (mean difference -6.4 on the Oswestry Disability Index, 95% CI -9.4 to -3.4), but no significant difference in pain scores and no difference at one year.

Epidural steroid injections offer a different delivery route. They provide short-term (2-6 week) pain relief for radiculopathy in some patients but do not reduce the long-term need for surgery [10]. The distinction between oral and epidural steroids matters: systemic exposure carries different risk profiles than targeted injection.

Drugs That Cause Back Pain as a Side Effect

The pharmacologic causes of back pain are underappreciated in clinical practice. Several major drug classes list back pain as an adverse event in their prescribing information, and clinicians should consider medication review when a patient presents with new or worsening back pain.

Statins. HMG-CoA reductase inhibitors are the most commonly prescribed drug class worldwide, and musculoskeletal complaints are their most frequent non-hepatic side effect. Back pain appears as an adverse event in key trials of atorvastatin, rosuvastatin, and simvastatin at rates of 3-5%, compared with 2-3% in placebo arms [11]. Statin-associated myalgia affects 5-10% of users in observational studies, and back muscles are a common site. The mechanism likely involves mitochondrial dysfunction and coenzyme Q10 depletion in skeletal muscle [12].

Aromatase inhibitors. Anastrozole, letrozole, and exemestane cause arthralgia and back pain in 35-50% of breast cancer patients, typically within the first three months of therapy. In the ATAC trial (N=9,366), musculoskeletal events occurred in 35.6% of patients on anastrozole versus 29.4% on tamoxifen [13]. This side effect is the leading cause of treatment discontinuation in this population.

Fluoroquinolone antibiotics. Ciprofloxacin, levofloxacin, and moxifloxacin carry an FDA black box warning for tendinitis, tendon rupture, and other musculoskeletal adverse effects [14]. Back pain and myalgia are reported in 1-2% of users in clinical trials, but post-marketing surveillance suggests higher real-world rates, particularly in patients over 60 or those taking concurrent corticosteroids.

Bisphosphonates. Alendronate and zoledronic acid can cause musculoskeletal pain, including severe back pain, in 2-5% of patients. The FDA issued a safety communication in 2008 noting reports of severe, sometimes incapacitating, bone, joint, or muscle pain in bisphosphonate users [15].

GLP-1 receptor agonists. Back pain appears as an adverse event in the prescribing information for semaglutide and tirzepatide. In the STEP-1 trial (N=1,961), back pain was reported in 6.6% of patients receiving semaglutide 2.4 mg versus 5.6% on placebo [16]. While the difference is small, patients starting GLP-1 therapy should be aware of this possibility.

Other Drug-Related Causes Worth Knowing

Isotretinoin (Accutane). Back pain and myalgia occur in up to 15% of patients on isotretinoin for acne, often dose-dependent and reversible upon discontinuation [17]. Teenagers and young adults on this medication may not connect their back symptoms to the drug.

Proton pump inhibitors (PPIs). Long-term PPI use (omeprazole, pantoprazole) has been associated with an increased fracture risk, particularly vertebral fractures. A 2012 meta-analysis in Osteoporosis International found a 29% increased risk of spine fractures with PPI use exceeding one year (OR 1.29 to 95% CI 1.15-1.46) [18]. Back pain from occult vertebral fractures in long-term PPI users is an underrecognized presentation.

Testosterone replacement therapy. Back pain is listed as an adverse event in clinical trials of testosterone gels and injections at rates of 3-4%. The mechanism is unclear and may relate to changes in body composition or fluid retention rather than direct musculoskeletal toxicity.

A Practical Medication-Review Approach

When a patient presents with back pain that does not fit a clear mechanical or anatomic pattern, a systematic medication review is warranted. Start by documenting all medications initiated or dose-adjusted within the preceding 90 days. Cross-reference each drug against its prescribing information for musculoskeletal adverse events. Consider a trial withdrawal or substitution for any suspect agent, with appropriate monitoring. NSAIDs remain the most reliable first-line treatment for nonspecific low back pain, while duloxetine is the best-studied option for the chronic form. Avoiding acetaminophen monotherapy and deferring opioids to last-line status aligns with current guideline recommendations [2].