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Birmingham and Solihull Mental health NHS Foundation Trust
Better Together
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Pharmacy update:The prescribing of gabapentin and pregabalin in prisons

Gabapentin and pregabalin are known anecdotally and via some published evidence to be highly sought after by some patients attending prison healthcare, either for their own use or for trading. Other evidence suggests anecdotal examples of abuse in the wider community. Both these medicines are indicated for epilepsy, neuropathic pain and generalised anxiety disorder.The latter two indications are the more common for both medicines in primary care and prison settings and are covered by NICE guidelines.

A recent national audit has investigated the use of gabapentin and pregabalin within 94 prison settings.  The audit covered 1819 prisoners who were prescribed gabapentin or pregabalin in 86 of the 94 prisons included. There was no prescribing in eight sites. 
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Prescribing of gabapentin/pregabalin was found to occur in around 2.82 per cent of the prison population.  This is estimated to be twice that of the general population but could be higher. Prescribing was higher in training prisons and Category A prisons compared to other prison categories. Youth offender institutions had the lowest rates of prescribing. Most prescribing was within the licensed dose range and frequency.
Prescribing costs across prisons were estimated at £1.4 million per annum. There is scope for cost savings by bringing prescribing rates closer to the general community.

For prisoners prescribed gabapentin/pregabalin, 84 per cent had a documented indication. One in six prisoners had no recorded indication. Over half of prescribing is for neuropathic pain but 22 per cent of unlicensed prescribing is for other pain indications. Further work would be needed to establish the robustness of the diagnosis of neuropathic pain and whether prevalence is higher within prisons compared to the general community.

Two thirds of prisoners had either medicine initiated in prisons. Of the rest, some may be initiated in primary care but others may have been initiated in prisons. As prisoners are often moved around the prison establishment, it can be difficult to establish initiation dates. One third of prisoners have taken gabapentin/pregabalin for less than nine months but a further third have taken these medicines for over three years. For 82 per cent of prisoners, medication reviews are documented to happen at least every six months.

Over half of prisoners on gabapentin/pregabalin have a history of substance misuse and 47 per cent are taking concurrent methadone or buprenorphine, with which gabapentin/pregabalin can increase the risk of respiratory depression. Many others are co-prescribed opioids for pain, particularly tramadol. The use of low dose tricyclic antidepressants with gabapentin/pregabalin is low. This may indicate a reluctance to use these within the prison for neuropathic pain.

The local picture

Locally within HM Prison Birmingham, we have been aware of the potential for abuse for some time and have taken steps to limit prescribing to those with a clear indication as far as possible. Prescribing rates are lower than the norm for prisons and prisoners on gabapentin/pregabalin will have both indication and medicines use reviewed regularly. In addition since this report, the prison healthcare service is establishing a register of prisoners on these two medicines to support monitoring of use and to facilitate regular review.  

Given the potential for prisoners to request gabapentin/pregabalin from their GP, once released from prison, the prison GPs will be writing to any prisoner’s GP where there is a history of illicit drug use and/or dependence to prescribed medication highlighting any medicines, including gabapentin/pregabalin that are not considered to be clinically appropriate and pose too high a risk of addiction, dependence, tolerance, or overdose.

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To date, most of the examples of abuse of gabapentin/pregabalin have occurred in prison establishments.  There are some examples in community patients. This abuse can be either personal or for diversion.  These medicines are often the focus of medication review given their relatively high cost and potential for savings in primary care. GPs are advised to be vigilant for the potential for abuse of gabapentin/pregabalin, particularly for people recently discharged from prisons. HM Prison Birmingham will be writing to GPs to highlight prisoners for whom a range of drugs of abuse should not be considered for prescribing including gabapentin/pregabalin.

Update by Nigel Barnes, director of pharmacy
August 2013

Ref:  Farmer D. (2013) The prescribing and management of gabapentin and pregabalin in HM Prisons and immigration removal centres In England. Collaborative Audit Report. East and South East England Specialist Pharmacy Services.