(P-090) Classification of Gabapentinoids as Controlled Drugs Reduced Gabapentinoid Prescriptions in Primary Care in England

Background: Following a rapid and marked increase in gabapentinoid prescriptions in the United Kingdom (UK), the Advisory Council on Misuse of Drugs (ACMD) raised concerns of misuse and associated harm in January 2016. In April 2019, gabapentinoids were classified as Class C Controlled Drugs obligated to hand-signed prescriptions and not allowed automatic refills. However, the impact of gabapentinoid reclassification has not been studied.

Objectives: This study aimed to assess the impact of gabapentinoid classification on gabapentinoid prescriptions dispensed in English primary care.

Methods: This cross-sectional study used national practice-level gabapentinoid dispensing data from the UK National Health Service (NHS) Business Services Authority from April 2013 to November 2020 in England. The monthly number of registrants in each general practice were retrieved from the NHS Digital. The effect of the interventions, i.e. gabapentinoid classification in April 2019 and ACMD advisory letter issued in January 2016, on monthly gabapentinoid utilisation (measured as defined daily doses per 1000 registrants) was tested using an autoregressive integrated moving average model. The coefficients were reported for pre-ACMD trend (β1) and the changes in amount at ACMD letter issued (β2), trend of post-ACMD (β3), amount at classification (β4), and trend of post-classification (β5).

Results: Classification of gabapentinoids as controlled drugs significantly reduced the amount (β4: -16.82, P=0.001) and post-classification trend (β5: -1.04, P=0.011) of monthly gabapentinoid utilisation. The ACMD advisory letter did not impact the amount but significantly reduced the previously increased trend (β3: -1.20, P<0.001) of monthly gabapentinoid utilisation. The amount of monthly gabapentin (β4: -10.50, P=0.002) and pregabalin (β4: -8.06, P<0.001) utilisation both significantly decreased in April 2019 when the gabapentinoid classification came into effect.

Conclusions: Classification of gabapentinoids as controlled drugs significantly reduced the amount and trend of gabapentinoid utilisation in English primary care. The reduction started when the ACMD letter issued in January 2016. The potential substitution effect of gabapentinoids and other medications (e.g. anti-epilepsy or pain medicines) warrants further studies.