A new Swedish study published last week in the British Medical Journal has found that treatment with gabapentinoids - a group of drugs used for epilepsy and other conditions - is associated with a number of harms including an increased risk of suicidal behaviour, unintentional overdose, injuries, and road traffic incidents.
The drugs examined in the study were pregabalin (Lyrica) and gabapentin (Neurontin). Data from almost 200,000 people aged 15 or older on the Swedish Prescribed Drug Register (2006 and 2013) was analysed.
The researchers compared the risk of harms during treatment periods with baseline risk during periods without treatment.
After taking account of potentially influential external factors, they found that participants were at a 26% increased risk of suicidal behaviour or death from suicide, a 24% increased risk of unintentional overdose, a 22% increased risk of head or body injuries, and a 13% increased risk of road traffic incidents or offences.
They found no link between gabapentinoid treatment and violent crime.
When drugs were examined separately, they found that only pregabalin, not gabapentin, was associated with increased risks of harm. They also found that risks were greatest among 15 to 24 year-olds. The authors suggest that as a result, treatment guidelines for young people should be reviewed. They also conclude that further research is needed to better understand the increased risks found in adolescents.
A number of weaknesses are highlighted in the study including that the study's design means that it cannot prove that the drug causes risky behaviours, only that it seems to be connected. The study was also not able to fully account for drug adherence or any interplay between alcohol and illicit drug use. The researchers were unable to rule out factors such as young people's higher odds of using alcohol or illegal drugs along with a gabapentinoid.
Previous studies have also linked gabapentinoids to suicidal behaviour and overdose related deaths, but findings have been inconsistent and data on longer term harms are lacking.
There are also concerns over the recreational use of these drugs and earlier this year the UK introduced prescribing restrictions, reclassifying pregabalin as a Class C drug (making it illegal to possess without a prescription and illegal to supply or sell to others). There have also been calls in Ireland to control its use. The findings of the Swedish study suggest that it may be possible to treat pregabalin and gabapentin differently from a policy perspective, while recognising the importance of these drugs in treating epilepsy and other disorders.
The study highlights the importance of weighing up benefits and risks in prescribing these drugs and the importance of full, open patient communication.