The Pharmaceutical Benefits Advisory Committee (PBAC) has knocked back PBS listing bids for two new formulations of pregabalin for neuropathic pain, citing the increased risk of misuse amid historic allegations of inappropriate prescribing for fibromyalgia.

In findings handed down a week ago, it also pointed to past analysis “which reported a larger number of PBS pregabalin scripts being prescribed by rheumatologists and psychiatrists”.

“This may indicate use outside the PBS restrictions,” it said.

“The PBAC considered that the potential for increased misuse and overdosing… could not be ruled out.”

It follows some controversy over the prescribing of pregabalin by rheumatologists since its listing on the PBS in 2013, restricted to the treatment of neuropathic pain and epilepsy.

Despite that, a report by the PBAC’s drug utilisation sub-committee two years later found rheumatologists were its top prescribers outside GPs, above even neurologists.

Both specialties’ prescribing paled in comparison with GPs, who collectively wrote more than four-fifths of all scripts for the drug in its first two years.

Nevertheless, the uptake by rheumatologists “may indicate treatment of fibromyalgia, which is outside the PBS restriction,” the sub-committee said.

“Based on the high discontinuation rate after one script, [the sub-committee] also considered that pregabalin may be being prescribed for acute pain.”

Dr Helen Cooley, a rheumatologist in Hobart and chair of the Australian Rheumatology Association’s therapeutics committee, said it was likely some rheumatologists had tried pregabalin for fibromyalgia in the past, but few would be initiating it now.

“There were some initial studies where it looked quite promising in fibromyalgia but I think as time has gone on, we have been less impressed with the efficacy,” she said.

“Further studies have also shown it really doesn’t have any role in the management of sciatica and certainly treatment guidelines have moved away from it.”

With the potential side effects an even bigger issue than efficacy, Dr Cooley said she generally worked to de-escalate pregabalin where possible in her own practice.

“I try to explain to my patients how medications actually form a very small part of treatment for fibromyalgia,’ she said.

“It’s really about looking at sleep and exercise and stress, which has pretty good evidence.”

While little prescribing data was available, this was likely the case across the specialty, Dr Cooley added.

The PBAC report covered two applications for Authority Required (Streamlined) listing of pregabalin at its intracycle meeting for May.

One of the applications was by Pfizer’s generics division Upjohn Australia for a controlled release formulation to treat neuropathic pain in adults, where the condition was refractory to other drugs.

The other, by a company called AFT Pharmaceuticals, requested listing of an oral solution based on the current indications.

In rejecting both, the PBAC said inquiries “outlined the risks associated with pregabalin use and did not identify an unmet need in the current neuropathic pain population”.

“The PBAC considered that the concomitant use of pregabalin with other drugs was a potential concern, noting that most pregabalin toxicity is associated with its use with opioids, benzodiazepines, alcohol or illegal drugs,” it added.