Friday, August 18, 2017

Benefits and Safety of Gabapentinoids in Chronic Low Back Pain

Chronic Low Back Pain (CLBP) is very common, with a lifetime prevalence between 51% and 80%. In majority, it is nonspecific in nature and multifactorial in etiology. Pregabalin (PG) and Gabapentin (GB) are gabapentinoids that have demonstrated benefit in neuropathic pain conditions. Despite no clear rationale, they are increasingly used for nonspecific CLBP. They necessitate prolonged use and are associated with adverse effects and increased cost. Recent guidelines from the National Health Service (NHS), England, expressed concerns on their off-label use, in addition to the risk of misuse. We aimed to assess the effectiveness and safety of gabapentinoids in adult CLBP patients.

Methods - Electronic databases of MEDLINE, EMBASE, and Cochrane were searched from their inception until December 20th, 2016. We included randomized control trials reporting the use of gabapentinoids for the treatment of CLBP of >3 months duration, in adult patients. Study selection and data extraction was performed independently by paired reviewers.

Results – Out of 1,385 citations, eight studies were included. Based on the interventions and comparators, studies were analyzed in 3 different groups. GB compared with placebo showed minimal improvement of pain in three studies. Three studies compared PG with other types of analgesic medication and showed greater improvement in the other analgesic group. Studies using PG and an adjuvant were not pooled due to heterogeneity, but the largest of them showed no benefit of adding PG to tapentadol. There were no deaths or hospitalizations reported. Compared with placebo, the following adverse events were more commonly reported with GB: dizziness, fatigue, difficulties with mentation and visual disturbances.

Conclusions and relevance – Existing evidence on the use of gabapentinoids in CLBP is limited and demonstrates significant risk of adverse effects without any demonstrated benefit. Given the lack of efficacy, risks, and costs associated, the use of gabapentinoids for CLBP merits caution. There is need for large high-quality trials to more definitively inform this issue.

My Take:
This is the way studies look when published, minus a lot of the statistical data that I eliminated. The National Institutes of Health takes studies like this then publishes online news articles that are more public friendly. Those online reports are the source of many of my blogs.

Using a drug “off label” is legal and common practice when a physician has clinical experience that shows that the drug can be effective in treating a condition for which the drug has not been approved.

The gabapentinoids were originally prescribed as antidepressants. However, physicians began using the drugs to treat neuropathy after diabetic patients reported marked improvement in their neuropathic symptoms with the use of these drugs.

This practice became so broad spread that the drug company went back and did the research to demonstrate gabapentinoids were effective in treating neuropathy. They re-released the drug as Gabapentin.

Now these neuropathy drugs are being used off label to treat CLBP with no evidence of neuropathy.

I face the same dilemma with the use of St. John’s wort or inositol. Both are quite effective in treating neuropathy but have little or no benefit in the treatment of CLBP without neuropathy.

St. John’s wort has several drug interactions, including the gabapentinoids. It enhances the cytochrome P-450 pathway in phase 1 liver detoxification often removing prescription drug before they have their desired effect.

Inositol has none of these issues. There are no reported side effects and no drug interaction. However, I reserve the use of inositol for patients that have some evidence of neuropathy. Although it is often effective at reducing or eliminating the symptoms of neuropathy, like the gabapentinoids, it has little or no effect on CLBP. It’s just a lot safer to use.

The Bottom Line:
If you are taking GB or PG for CLBP without evidence of neuropathy, please present this information to your physician. If you suffer from neuropathy with or without CLBP consider the use of inositol. It’s safe, without side effects, and often effective.

Source: August 15, 2017 PLOS Medicine

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