Acetaminophen and Steroids: How Effective Are They for Pain?

August 21, 2014

The results of several recent studies on both drug classes may come as a surprise. Will they change the way you prescribe either or both for pain?

Acetaminophen and steroids, administered either orally or via injections, have long been mainstays in the treatment of pain. However, several new studies indicate that they may be less efficacious than has been widely thought.

One study compared acetaminophen with placebo for patients with acute low back pain (ALBP).1 The primary outcome measure was recovery from the pain, defined as a score of 0 or 1 on a 0 to 10 pain scale for 7 consecutive days. Subjects were assigned to groups that took acetaminophen on either a fixed schedule or an as-needed basis, or placebo. No differences were found among either of the acetaminophen groups or the placebo group with regard to the primary measure or to secondary measures, including pain intensity and functioning.

This study was looked solely at ALBP, so it certainly is possible that acetaminophen is more efficacious for other forms of pain. Most guidelines on pain management, including those on ALBP, recommend that acetaminophen be a starting medication for patients unless there was a contraindication to its use. The authors of an accompanying editorial did not feel this recommendation should be changed on the basis of a single study, despite their acknowledgement of the study’s quality.2 I would agree with this.

However, we should consider how many patients are benefiting from acetaminophen when we prescribe it-especially in the case of opioid-acetaminophen combination drugs.

There have been two primary reasons given for prescribing these drugs instead of an opioid alone. The first is that the acetaminophen actually provides additional pain relief. The other is that the inclusion of acetaminophen reduces the chance of physicians prescribing too high a dose of an opioid, decreasing the likelihood of patient abuse or overdose.

There is nothing to indicate that the latter reason is true now or that it ever was valid. Opioid-acetaminophen combination drugs are the most abused opioid drugs and the ones most frequently involved in overdoses-clearly they haven’t had an impact on these problems.

So, the only apparent reason we have for combining acetaminophen with opioids is additional pain relief. It has always been questionable whether acetaminophen provides this; the new study suggests that it may not.

Personally, I don’t believe that most physicians who prescribe opioid-acetaminophen combination drugs do so because they think the acetaminophen is offering additional relief, but do it, rather, out of habit. However, since acetaminophen can have significant adverse effects if taken in excessive doses, most notably hepatic toxicity, it would seem that there should be a valid reason for placing patients at risk for this, beyond physicians simply being used to prescribing combination drugs.

As far as using non-steroidal anti-inflammatory drugs (NSAIDs) as an alternative to acetaminophen, the authors of the study note that there is no evidence that the former are any more efficacious than the latter for ALBP.

Prednisone, too?

This implication that NSAIDs may not be that helpful for ALBP may extend to oral steroids, too. Another new study examined the use of oral prednisone for the treatment of ALBP in an emergency department (ED) and found similar results.3

The study included patients who came to an ED with ALBP of 2 or less days’ duration that began after a bending or twisting injury. Those with identifiable pathology for the pain or evidence of trauma or motor deficits were excluded. Participants were started either on a 5-day course of prednisone or placebo.

Those who took prednisone did no better than those on placebo with regard to pain level or functioning. Furthermore, those who took prednisone were more than twice as likely to seek additional medical treatment during the 5-day period (40% vs 18%). Unfortunately, the authors of the study do not offer any explanation for this finding.

The use of steroids for ALBP has rested on the theory that in the absence of identifiable pathology, the pain is most likely due to an inflammatory process, something which has never been proven. Although I can’t recall seeing any studies on it, my general sense is that the use of oral steroids for ALBP has become less frequent than it once was. One can only speculate whether this is due to clinical practice observations about their lack of efficacy.

Two other new studies call into question how beneficial steroid injections are for two conditions for which they are frequently used: spinal stenosis and shoulder pain.

In the first study, patients with lumbar spinal stenosis received either epidural injections with glucocorticoids and lidocaine or lidocaine alone.4  At a 6-week follow-up, no differences were found between the two groups with regard to pain intensity or functioning.

As there was no placebo group, the authors were unable to determine whether the lidocaine was providing a significant benefit.

The results of this study, together with a review of the literature on epidural steroid injections that found little evidence that they were of much benefit for sciatica, should certainly make us question if this treatment is worthwhile.5

In another new study, steroid injections were compared with manual physical therapy (MPT) for shoulder pain secondary to shoulder impingement syndrome, which included multiple pathologies such as bursitis, rotator cuff tendinopathy, and partial rotator cuff tear.6  Sixty-two percent of patients who received the injections received only one, while the other 38% received two or more. Virtually all of the MPT patients received six 30-minute sessions over a 3-week period. Follow-up occurred at 1, 3, and 6 months and at 1 year.

Once again, there was no difference between the two groups with regard to level of pain or functioning. However, those who received the injections were more likely to have one or more subsequent visits to their primary care physician for their pain over the next year than those who received MPT (60% of injection patients vs 37% of MPT patients).

As an accompanying editorial noted, the lower need for additional care among MPT patients may reflect that this type of therapy “may provide an opportunity for therapists to better address patients’ concerns about their condition, provide reassurance, or educate patients in self-management.”7

I am in complete agreement with this view. Multiple studies have found that the best treatment for most cases of chronic pain involves educating patients in the ways that they can help themselves and offering support as they do this, rather than treatments that physicians do to patients.

The editorial does note that six sessions of MPT is usually more expensive than a single injection and that the latter treatment may be chosen for this reason. However, it also noted that the reduced need for visits to primary care physicians no doubt offsets at least part of this cost, although this wasn’t addressed in the study.

I believe this is an important point. Often in measuring healthcare costs, only the direct costs of treatments are considered, with little attention paid to possible secondary savings that may also be significant.

What drugs and supportive methods do you find most effective in pain mangement?
Will knowledge of these studies affect your use of either agent or both?

Please use the Comments section below References to let us know.

 

References:

1. Williams CM, Maher CG, Latimer J, et al. Efficacy of paracetamol for acute low-back pain: a double-blind, randomised controlled trial. Lancet. 2014 Jul 234; doi: 10.1016/S0140-6736(14)60805-9. [Epub ahead of print]

2. Koes B, Enthoven W. Do patients with acute low-back pain need paracetamol? Lancet. 2014 Jul 23;doi:10.1016/S0140-6736(14)60978-8. [Epub ahead of print]

3. Eskin B, Shih RD, Fiesseler FW, et al. Prednisone for emergency department low back pain. J Emerg Med. 2014;47:65-70.

4. Friedly JL, Comstock BA, Turner JA, et al. A randomized trial of epidural glucocorticoid injections for spinal stenosis. N Engl J Med. 2014;371:11-21.

5. Pinto RZ, Maher CG, Ferreria ML, et al. Epidural corticosteroid injections in the management of sciatica: a systemic review and meta-analysis. Ann Intern Med. 2012;157:865-877.

6. Rhon DI, Boyles RB, Cleland JA. One-year outcome of subacromial corticosteroid injection compared with manual physical therapy for management of the unilateral shoulder impingement syndrome: a pragmatic randomized trial. Ann Intern Med. 2014;161:161-169.doi:10.7326/M13-2199

7. Coombs BK, Vincenzino B. Pragmatic study of corticosteroid injections and manual physical therapy for the shoulder impingement syndrome. Ann Intern Med. 2014;161:224-225.doi:10.7326/M14-1405.