Pain

Pregabalin used inappropriately for back pain and fibromyalgia: PBS data


Many people are being prescribed pregabalin for inappropriate indications such as low back pain and fibromyalgia, an Australian study suggests.

The drug is recommended for neuropathic pain but usage trends revealed by PBS data suggests it is being used inappropriately in low doses for short term treatment of acute pain and in combination with opioids, according to researchers from the University of NSW.

Sampling of pregabalin PBS prescription dispensing data for more than 130,000 patients showed that after pregabalin was subsidised on the PBS in 2013 there was a three-fold increase in its use but also an increasing trend for it to be used for short duration treatment.

More than one in three patients (38%) only had one dispensing, and the proportion of patients discontinuing pregabalin within a year increased from 77% in 2013/14 to 86% in 2017/18.

This suggested either poor tolerability of pregabalin  or that people were using for indications other than chronic neuropathic pain, the study authors said.

There was also evidence that many patients were not having pregabalin titrated up to an effective dose for neuropathic pain.

One third (37.5%) of patients were initiated on the lowest strength pregabalin capsule (25 mg) and only 31% later up‐titrating to a higher strength. The study authors noted that Australian guidelines suggest starting patients on doses of 75 mg pregabalin and that for neuropathic pain it is generally effective in doses of at least 150 mg or 300 mg daily.

Also of concern were the high rates of opioid use, which is not recommended in neuropathic pain, with 47% and 53% of patients being dispensed opioids within 180 days before and after pregabalin initiation.

Low rates of prior antidepressant use also suggested that most new pregabalin use was not consistent with the PBS restriction for neuropathic pain refractory to other first-line medicines, the study authors said.

They suggested that prescribers may be confused by inconsistencies between Australian guidelines and PBS criteria that restrict pregabalin to second line use in the treatment of neuropathic pain.

Prescribing may also be driven by ‘off label’ use for fibromyalgia and anxiety, which are licensed indications for pregabalin in some other jurisdictions but not in Australia.

Given the abuse potential and risk of adverse effects with pregabalin, Australian regulators may need to consider restrictions such as those in the UK, where pregabalin has been re-classified as a controlled drug, they suggested.

“The variations in recommendations and approvals by health regulatory bodies worldwide, compounded by drug company marketing for off-label conditions are no doubt contributing to the uncertainty around the optimal use of pregabalin; revision of PBS restrictions to be more in line with contemporary practice may be warranted,” they wrote.

The findings are published in the British Journal of Clinical Pharmacology.

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