Nonspecific low back pain affects most people at some time in their lives. Although it is frequently short-lived, it accounts for a disproportionate number of healthcare encounters and is a major cause of lost time from work. Acetaminophen is commonly the first-line analgesic prescribed and is recommended in most clinical practice guidelines. Despite this, there is credible evidence that acetaminophen may not be an optimal first choice and that its role in treating acute and subacute low back pain needs to be reevaluated.
What Is the Clinical Question?
What are the efficacy and safety of acetaminophen in reducing low back and neck pain?
30-Day Unplanned Readmission or Death
Among the eligible patients, 1269 (29.5%) were readmitted or died within 30 days after their discharge from the index hospitalization. The proportion of patients who had the composite end point and had a persistent hyponatremia during the index hospitalization was 33.7% (n = 606) (Table 2). The crude OR for having a 30-day unplanned readmission or death was 1.40 (95% CI, 1.23-1.60). In a multivariable logistic regression, the persistent hyponatremia was associated with a statistically significant 45% increase in the odds of readmission or death within 30 days after discharge (adjusted OR, 1.45; 95% CI, 1.27-1.67) (Table 3). Further factors statistically significantly associated with the primary outcome of interest were black race, higher number of previous admissions, unplanned hospitalization (vs elective), longer length of stay, lack of ischemic heart disease, and presence of cancer. We found no effect modification for all baseline characteristics, except for length of stay (Pvalue for interaction = .01) (Figure 2): The effect of persistent hyponatremia on the risk of 30-day readmission or death appeared higher with increasing length of stay.
What Are the Parameters of Our Evidence Search and Basis for Our Conclusion?
Population: Adults with neck or low back pain
Setting: outpatient
Intervention: acetaminophen
Comparator: placebo
Outcomes: pain, disability, and quality of life
What Do Clinical Guidelines Say?
Institute for Clinical Systems Improvement. Adult Acute and Subacute Low Back Pain, 20121 (Appraisal of Guidelines for Research and Evaluation II Score: 82%).
- Acetaminophen: Use over-the-counter short-term acetaminophen or nonsteroidal anti-inflammatory drugs to help ease the pain or inflammation in the lower back. (No quality or strength of recommendation given.)
- If nonsteroidal anti-inflammatory drugs upset stomach, use acetaminophen.
- Patients need to be aware that acetaminophen has the risk of serious liver disease.
- Other medication is recommended, including nonsteroidal anti-inflammatory drugs, opioids, and muscle relaxants.
An Updated Overview of Clinical Guidelines for the Management of Non-specific Low Back Pain in Primary Care, 20102 (Appraisal of Guidelines for Research and Evaluation II Score: unavailable).
- Reassure patients (favorable prognosis).
- Advise to stay active.
- Prescribe medication if necessary (preferably time-contingent).
- First-line is paracetamol.
- Second-line is nonsteroidal anti-inflammatory drugs.
- Consider muscle relaxants, opioids, or antidepressant and anticonvulsants.
- Discourage bed rest.
- Do not advise a supervised exercise program.
Author Commentary
We searched PubMed, Embase, and the Cochrane Database of Systematic Reviews and retrieved 2 guidelines and 1 recent high-quality systematic review summarizing 3 randomized trials specifically addressing treatment with acetaminophen for low back and neck pain.5 One of the 3 trials demonstrated a low risk of bias, but the overall quality across the body of evidence by outcome was moderate to high, as noted in the evidence (Table).
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-Megan Sands-Lincoln, PhD, MPH, David R. Goldmann, MD
This article originally appeared in the August 2016 issue of The American Journal of Medicine.
