Despite escalating prescriptions, nerve pain drug offers no relief for sciatica

Sciatica is a disabling condition characterised by pain in the leg along the distribution of the sciatic nerve. It can be accompanied by back pain, tingling, numbness, reduced strength and reflex changes in the leg.

Sciatica is most commonly caused by irritation of the nerve roots emerging from the lower spine. For this reason it is often considered a type of nerve pain.

It is estimated that around 5 to 10% of people with low back pain have sciatica, equating to around 200,000 to 400,000 Australians. It is notoriously difficult to treat sciatica with over-the-counter medications and complementary therapies.

Our study released today examines the commonly prescribed nerve pain treatment pregabalin for acute and chronic sciatica. The results show that pregabalin does not improve pain symptoms or function, but is associated with unwanted side effects such as dizziness when compared to a placebo.

Huge uptake of new drug

Medicines that have shown to be effective for treating nerve pain were considered to be an exciting new treatment option for sciatica.

These include drugs used to treat epilepsy, such as gabapentin and pregabalin. These medicines, sometimes called gabapentinoids, seem to work by preventing normal conduction of pain signals along a nerve.

Pregabalin became subsidised by the Australian government for nerve pain in 2013 and quickly became widely prescribed for conditions such as sciatica. In its first year of listing, nearly 1.4 million prescriptions were written and in its second year, this figure increased to 2.4 million. This was 32% more than the government predicted.

Since its first approval in 2004 pregabalin has become the most widely prescribed medicine for nerve pain globally, with worldwide sales of between US$3-5 billion annually. The astonishing growth is likely to be a consequence of many factors but may partly be a reflection of the lack of effective treatments for sciatica.

But while pregabalin has been shown to be effective for other types of nerve pain, there was little evidence it helped patients with sciatica. There were also emerging concerns of increased harmful effects, including risk of suicidality and misuse.

We designed our study to examine whether pregabalin is effective and has tolerable side effects in patients with sciatica.

Pregabalin does not work for sciatica

The research compared the effects of pregabalin against placebo (identical inactive capsules) in 207 patients with sciatica.

Patients were randomly assigned to take up to eight weeks of pregabalin or placebo, prescribed and monitored by a general practitioner or a medical specialist. To keep the results as unbiased as possible, patients, doctors and study staff were kept blinded to who was treated with pregabalin and who received placebo capsules.

This study found after eight weeks there was no difference in the severity of leg pain between those who took pregabalin and those who took placebo capsules. The same result was seen at one year. There were also no differences in other relevant outcomes, such as back pain severity and function, at either eight weeks or one year.

However, people who took pregabalin reported more adverse effects. The most common adverse effect reported in the trial was dizziness.

The study shows that taking pregabalin does not improve your sciatic symptoms when compared with placebo, but you are more likely to have adverse effects when taking pregabalin.

Treatment options for sciatica

Few alternative treatment options exist for people suffering from sciatica.

There is limited data describing the effects of nonsurgical treatments such as exercise, spinal manipulation or acupuncture on sciatica.

There is also no convincing evidence to show medicines such as anti-inflammatory drugs, oral corticosteroids or opioid analgesic medicines are effective. Epidural corticosteroid injections have been shown to have a small benefit in the short-term only.

Surgery confers a short-term effect in selected patients with sciatica, but after a year people with sciatica who have not had surgery do just as well as people who’ve had the procedure.

The good news is that sciatica does get better with time. It’s important to stay as active as possible and to avoid prolonged bed rest (as this can delay recovery).

If you’re currently taking pregabalin, speak to a doctor about your condition, and mention any improvement or adverse effects you’ve experienced since starting pregabalin. It’s important not to stop pregabalin abruptly – usually doses should be reduced slowly over a few weeks. Abruptly stopping pregabalin can have some ill effects and should be done with care, close monitoring and advice from a doctor.

It’s unfortunate, but we do not currently have a lot of effective treatment options for people with sciatica. Speak to your doctor or treating clinician (such as a physiotherapist) about what may be appropriate for you, including specific advice on how you can stay as active as possible.

Christine Lin receives a fellowship from the National Health and Medical Research Council of Australia (NHMRC). The PRECISE Study was funded by a grant from NHMRC, and Pfizer Australia provided the study active and placebo capsules free of charge. Investigators of the PRECISE study maintained full autonomy on the study design, conduct and report.

Andrew McLachlan receives funding as the Program Director of the National Health and Medical Research Council of Australia (NHMRC) Centre for Research Excellence in Medicines and Ageing. The PRECISE Study on pregabalin in sciatica was funded by a project grant from NHMRC, and Pfizer Australia provided the study active and placebo capsules free of charge. Investigators of the PRECISE study maintained full autonomy on the study design, conduct and report. Andrew McLachlan has served as an external consultant related to regulatory submissions for Pfizer and Hospira.