The number of patients prescribed both gabapentinoids and an opioid has tripled over the last decade, with 20% of all patients taking either gabapentin or pregabalin also taking an opioid, according to a new study.
Researchers from France and Canada studied prescribing levels in the UK and found that the proportion of the general population prescribed both opioids and gabapentinoids rose from 56.4 to 148.1 per 100,000 persons per year for gabapentin and from 28.7 to 91.2 for pregabalin.
They also saw that the overall number of patients prescribed gabapentinoids by GPs tripled from 2007 to 2017.
The study team called for patients taking this combination of drugs to be closely monitored, as it ‘increases the risk of serious side-effects and overdose’, while GPs stressed the importance of the initial diagnosis being ‘accurate’ and highlighted the lack of assessment guidance in the NICE neuropathic pain guidelines.
The study, published in JAMA, looked at trends in gabapentin and pregabalin prescriptions in UK primary care from 1993-2017.
Researchers used a UK database of primary care medical records (CPRD) with more than 15m patients, and identified all those registered for at least one day between 1993 and 2017.
They found that from 2007 to 2017, the rate of patients newly treated increased from 230 to 679 per 100,000 persons per year for gabapentin, and from 128 to 379 per 100,000 persons per year for pregabalin.
Meanwhile the rate of patients with a co-prescription for opioids and/or benzodiazepines also increased from 56.4 to 148.1 per 100,000 persons per year for gabapentin, and from 28.7 to 91.2 per 100,000 persons per year for pregabalin.
Off-label prescribing increased, from 58.7 to 216.0 per 100,000 persons per year for gabapentin and from 34.7 to 117.8 per 100,000 persons per year for pregabalin.
The researchers found that by 2017, 21.8% of patients newly treated with gabapentin and 24.1% newly treated with pregabalin received a concomitant prescription, primarily for opioids, while off-label prescriptions accounted for 52% of gabapentin and 54.8% of pregabalin prescriptions with an identified indication in 2017.
The findings come after the Government announced in October that pregabalin and gabapentin will be reclassified as class C drugs, starting from April 2019. This will add a number of restrictions, such as GPs needing to sign their patients’ prescription in person and pharmacists dispensing the items within 28 days.
The change follows a drastic rise in prescribing, thought to be the result of NICE recommending gabapentinoids as a first-line treatment for neuropathic pain in 2013.
The paper said: ‘The rate of patients newly treated with gabapentinoids has tripled from 2007 to 2017 in primary care in the United Kingdom. By 2017, 50% of gabapentinoid prescriptions were for an off-label indication and 20% had a co-prescription for opioids…
‘Given the safety concerns of gabapentinoids and the lack of robust evidence supporting their efficacy in cases of non-neuropathic pain, caution is necessary when prescribing gabapentinoids, especially among patients also prescribed opioids.’
Study author and assistant professor Christel Renoux, from McGill University, Canada, said: ‘These trends are of concern because co-prescription with these medications increases the risk of serious side-effects and overdose in combination with opioids use.
‘Therefore, the potential benefit of such combination should be carefully weighed against risks and these patients should be closely monitored.’
According to the Office for National Statistics, there were 165 drug-related deaths involving gabapentin or pregabalin across England and Wales in 2016, with 147 of these involving an opiate.
But RCGP clinical champion for chronic pain Dr Martin Johnson said that while the figures seem ‘concerning’, it’s a ‘complex’ area.
He said: ‘On first glance the gabapentinoid prescriptions are concerning however, pain is complex and we don’t know the reasons for the gabapentin or pregabalin prescriptions (e.g. pain, anxiety, migraine, epilepsy).’
‘The key with pain, especially neuropathic pain, is making an accurate diagnosis at the start – there are no assessment guidelines in the NICE neuropathic pain guidelines though others – such as the British Pain Society guidelines – do exist.
‘One question I always ask is how often are these patients being followed up, as once stable they should be reviewed at least once annually according to available guidance.’