The study in the New England Journal of Medicine also found people taking the drug pregabalin reported nearly twice as many adverse effects than those receiving the placebo.
Associate Professor Christine Lin from The George Institute for Global Health, Sydney, said: "We have seen a huge rise in the amount of prescriptions being written each year for patients suffering from sciatica. It's an incredibly painful and disabling condition so it's no wonder people are desperate for relief and medicines such as pregabalin have been widely prescribed.
"But, until now there has been no high quality evidence to help patients and doctors know whether pregabalin works for treating sciatica. Our results have shown pregabalin treatment did not relieve pain, but did cause side effects such as dizziness."
Sciatica is pain, tingling or numbness along the distribution of the sciatic nerve, most commonly caused by irritation of the nerve roots. Pain is mostly felt in the lower limbs but can be accompanied by back pain.
Since its first approval in 2004 pregabalin (sold as Lyrica) has become the most widely prescribed medicine for neuropathic pain globally, with worldwide sales of between $3-5 billion annually.
At any one time around 12% of the world's population has low back pain. It is estimated that around five to 10% of people with low back pain will have sciatica.
Researchers from the Musculoskeletal Division at The George Institute undertook the study after being increasingly concerned about the rise in the use of pregabalin, limited data on its effectiveness and fears over the drug's safety. One of the possible serious side effects is suicidal thoughts or actions. Pregabalin is used for a number of painful conditions that include neuropathic pain.
The research team at The George Institute followed 209 patients with sciatica in Sydney, Australia, who received pregabalin or a placebo capsule. After eight weeks there was no significant difference in pain intensity between the group taking pregabalin and those receiving the placebo and over one year no significant difference in the amount of days lost from work.
Despite the findings almost two thirds of patients on the study reported being very satisfied or satisfied with their drug regimen.
Associate Professor Christine Lin, of The George institute, said: "Over the course of eight weeks the levels of pain that patients experienced did decrease but the drop in pain was the same for both those taking the drug and those on placebo. It seems people associate a drop in pain being due to taking a capsule, rather than something which would happen naturally over time. GPs who are prescribing pregabalin should take note of these findings, and talk with their patients about other ways of managing and preventing pain.
"Unfortunately there are no drugs proven to work for people with sciatica and even epidural injections only provide a small benefit in the short term. What we do know is that most people with sciatica do eventually recover with time. It's also important to avoid bed rest and to stay as active as possible."
The team found no increase in the risk of self-harm, however the trial was not set up to detect risk of suicide so GPs are advised to exercise caution when prescribing.
This study was led by researchers from The George Institute in collaboration with researchers from The University of Sydney, University of New South Wales and Macquarie University.
Article: Trial of Pregabalin for Acute and Chronic Sciatica, Christine Lin, Ph.D. et al., New England Journal of Medicine, doi: 10.1056/NEJMoa1614292, published 23 March 2017.