Effect of a New Synergistic Combination of Low Doses of Acetylsalicylic Acid, Caffeine, Acetaminophen, and Chlorpheniramine in Acute Low Back Pain

Paracetamol Combination Therapy for Back Pain and Osteoarthritis: A Systematic Review and Meta-Analyses

BACKGROUND AND OBJECTIVE

Although paracetamol (acetaminophen) combined with other analgesics can reduce pain intensity in some pain conditions, its effectiveness in managing low back pain and osteoarthritis is unclear. This systematic review investigated whether paracetamol combination therapy is more effective and safer than monotherapy or placebo in low back pain and osteoarthritis.

METHODS

Online database searches were conducted for randomised trials that evaluated paracetamol combined with another analgesic compared to a placebo or the non-paracetamol ingredient in the combination (monotherapy) in low back pain and osteoarthritis. The primary outcome was a change in pain. Secondary outcomes were (serious) adverse events, changes in disability and quality of life. Follow-up was immediate (≤ 2 weeks), short (> 2 weeks but ≤ 3 months), intermediate (> 3 months but < 12 months) or long term (≥ 12 months). A random-effects meta-analysis was conducted. Risk of bias was assessed using the original Cochrane tool, and quality of evidence using Grading of Recommendations Assessment, Development and Evaluation (GRADE).

RESULTS

Twenty-two studies were included. Pain was reduced with oral paracetamol plus a non-steroidal anti-inflammatory drug (NSAID) at immediate term in low back pain (paracetamol plus ibuprofen vs ibuprofen [mean difference (MD) - 6.2, 95% confidence interval (CI) -10.4 to -2.0, moderate evidence]) and in osteoarthritis (paracetamol plus aceclofenac vs aceclofenac [MD - 4.7, 95% CI - 8.3 to - 1.2, moderate certainty evidence] and paracetamol plus etodolac vs etodolac [MD - 15.1, 95% CI - 18.5 to - 11.8; moderate certainty evidence]). Paracetamol plus oral tramadol reduced pain compared with placebo at intermediate term for low back pain (MD - 11.7, 95% CI - 19.2 to - 4.3; very low certainty evidence) and osteoarthritis (MD - 6.8, 95% CI - 12.7 to -0.9; moderate certainty evidence). Disability scores improved in half the comparisons. Quality of life was infrequently measured. All paracetamol plus NSAID combinations did not increase the risk of adverse events compared to NSAID monotherapy.

CONCLUSIONS

Low-to-moderate quality evidence supports the oral use of some paracetamol plus NSAID combinations for short-term pain relief with no increased risk of harm for low back pain and osteoarthritis compared to its non-paracetamol monotherapy comparator.

Nonopioid pharmacological management of acute low back pain: A level I of evidence systematic review

Acute low back pain (LBP) imposes a significant socioeconomical burden as it is the condition that, worldwide, cause the most disability. Nonetheless, the literature regarding the best pharmacological management of acute LBP is limited, and the indications available in the literature are conflicting. This work investigates whether the pharmacological management of acute LBP can effectively reduce pain and disability, and aims to identify which drugs show the highest efficacy. This systematic review was conducted according to the 2020 PRISMA statement. In September 2022, PubMed, Scopus, and Web of Science were accessed. All the randomized controlled trials investigating the efficacy of myorelaxants, nonsteroidal anti-inflammatory drugs (NSAIDs), and paracetamol for acute LPB were accessed. Only studies that investigated the lumbar spine were included. Only studies reporting on patients with acute LBP with symptom duration of less than 12 weeks were included. Only patients older than 18 years and with nonspecific low back pain were included. Studies that investigated the use of opioids in acute LBP were not considered. Data from 18 studies and 3478 patients were available. Myorelaxants and NSAIDs were effective in reducing pain and disability in acute LBP at approximately one week. The combination of NSAIDs and paracetamol was associated with a greater improvement than the use of NSAIDs alone, but paracetamol alone did not induce any significant improvement. Placebo was not effective in reducing pain. Clinical Significance: Myorelaxants, NSAIDs, and NSAIDs with paracetamol could reduce pain and disability in patients with acute LBP.

Can FDA-Approved Immunomodulatory Drugs be Repurposed/Repositioned to Alleviate Chronic Pain?

Pain is among the most widespread chronic health condition confronting society today and our inability to manage chronic pain contributes to the opioid abuse epidemic in America. The immune system is known to contribute to acute and chronic pain, but only limited therapeutic treatments such as non-steroid anti-inflammatory drugs have resulted from this knowledge. The last decade has shed light on neuro-immune interactions mediating the development, maintenance, and resolution of chronic pain. Here, we do not aim to perform a comprehensive review of all immune mechanisms involved in chronic pain, but to briefly review the contribution of the main cytokines and immune cells (macrophages, microglia, mast cells and T cells) to chronic pain. Given the urgent need to address the Pain crisis, we provocatively propose to repurpose/reposition FDA-approved immunomodulatory drugs for their potential to alleviate chronic pain. Repositioning or repurposing offers an attractive way to accelerate the arrival of new analgesics.

Non-steroidal anti-inflammatory drugs for acute low back pain

BACKGROUND

Acute low back pain (LBP) is a common health problem. Non-steroidal anti-inflammatory drugs (NSAIDs) are often used in the treatment of LBP, particularly in people with acute LBP. In 2008, a Cochrane Review was published about the efficacy of NSAIDs for LBP (acute, chronic, and sciatica), identifying a small but significant effect in favour of NSAIDs compared to placebo for short-term pain reduction and global improvement in participants with acute LBP. This is an update of the previous review, focusing on acute LBP.

OBJECTIVES

To assess the effects of NSAIDs compared to placebo and other comparison treatments for acute LBP.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, PubMed, and two trials registers for randomised controlled trials (RCT) to 7 January 2020. We also screened the reference lists from relevant reviews and included studies.

SELECTION CRITERIA

We included RCTs that assessed the use of one or more types of NSAIDs compared to placebo (the main comparison) or alternative treatments for acute LBP in adults (≥ 18 years); conducted in both primary and secondary care settings. We assessed the effects of treatment on pain reduction, disability, global improvement, adverse events, and return to work.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials to be included in this review, evaluated the risk of bias, and extracted the data. If appropriate, we performed a meta-analysis, using a random-effects model throughout, due to expected variability between studies. We assessed the quality of the evidence using the GRADE approach. We used standard methodological procedures recommended by Cochrane.

MAIN RESULTS

We included 32 trials, with a total of 5356 participants (age range 16 to 78 years). Follow-up ranged from one day to six months. Studies were conducted across the globe, the majority taking place in Europe and North-America. Africa and the Eastern Mediterranean region were not represented. We considered seven studies at low risk of bias. Performance and attrition were the most common biases. There was often a lack of information on randomisation procedures and allocation concealment (selection bias); studies were prone to selective reporting bias, since most studies did not register their trials. Almost half of the studies were industry-funded. There is moderate quality evidence that NSAIDs are slightly more effective in short-term (≤ 3 weeks) reduction of pain intensity (visual analogue scale (VAS), 0 to 100) than placebo (mean difference (MD) -7.29 (95% confidence interval (CI) -10.98 to -3.61; 4 RCTs, N = 815). There is high quality evidence that NSAIDs are slightly more effective for short-term improvement in disability (Roland Morris Disability Questionnaire (RMDQ), 0 to 24) than placebo (MD -2.02, 95% CI -2.89 to -1.15; 2 RCTs, N = 471). The magnitude of these effects is small and probably not clinically relevant. There is low quality evidence that NSAIDs are slightly more effective for short-term global improvement than placebo (risk ratio (RR) 1.40, 95% CI 1.12 to 1.75; 5 RCTs, N = 1201), but there was substantial heterogeneity (I² 52%) between studies. There is very low quality evidence of no clear difference in the proportion of participants experiencing adverse events when using NSAIDs compared to placebo (RR 0.86, 95% CI 0.63 to 1.18; 6 RCTs, N = 1394). There is very low quality evidence of no clear difference between the proportion of participants who could return to work after seven days between those who used NSAIDs and those who used placebo (RR 1.48, 95% CI 0.98 to 2.23; 1 RCT, N = 266). There is low quality evidence of no clear difference in short-term reduction of pain intensity between those who took selective COX-2 inhibitor NSAIDs compared to non-selective NSAIDs (mean change from baseline -2.60, 95% CI -9.23 to 4.03; 2 RCTs, N = 437). There is moderate quality evidence of conflicting results for short-term disability improvement between groups (2 RCTs, N = 437). Low quality evidence from one trial (N = 333) reported no clear difference between groups in the proportion of participants experiencing global improvement. There is very low quality evidence of no clear difference in the proportion of participants experiencing adverse events between those who took COX-2 inhibitors and non-selective NSAIDs (RR 0.97, 95% CI 0.63 to 1.50; 2 RCTs, N = 444). No data were reported for return to work.

AUTHORS' CONCLUSIONS

This updated Cochrane Review included 32 trials to evaluate the efficacy of NSAIDs in people with acute LBP. The quality of the evidence ranged from high to very low, thus further research is (very) likely to have an important impact on our confidence in the estimates of effect, and may change the estimates. NSAIDs seemed slightly more effective than placebo for short-term pain reduction (moderate certainty), disability (high certainty), and global improvement (low certainty), but the magnitude of the effects is small and probably not clinically relevant. There was no clear difference in short-term pain reduction (low certainty) when comparing selective COX-2 inhibitors to non-selective NSAIDs. We found very low evidence of no clear difference in the proportion of participants experiencing adverse events in both the comparison of NSAIDs versus placebo and selective COX-2 inhibitors versus non-selective NSAIDs. We were unable to draw conclusions about adverse events and the safety of NSAIDs for longer-term use, since we only included RCTs with a primary focus on short-term use of NSAIDs and a short follow-up. These are not optimal for answering questions about longer-term or rare adverse events.