Factors associated with co-prescription of opioids and gabapentinoids

Abstract

Background: gabapentin and pregabalin are commonly used for relieving neuropathic pain, but also could lead to diversion, dependence and tolerance, with adverse effects on the central nervous system, especially when co-prescribed with opioids. The rates of prescribing gabapentinoids have significantly increased over the last decade. However, limited research has investigated the impact of excessive prescribing, and the factors associated with the co-prescribing of opioids and gabapentinoids are unknown.Objectives: (1) to review existing evidence of the misuse of gabapentin and pregabalin systematically; (2) to examine the association between health outcomes/service use and co-prescribed opioids and gabapentinoids, after controlling for the potential confounders of socio-demographic factors and cancer.

Methods: (1) published literature on gabapentinoids misuse was searched systematically in key medical and pharmacy databases, and papers were selected based on inclusion/exclusion criteria (studies of adolescents and children, case studies and animal studies and irrelevant studies were excluded). After data abstraction and quality assessment, included citations were synthesised and summarised. (2) An existing dataset of 65,000 individuals in Tayside and Fife who had received at least one prescription of an opioid, with corresponding prescribing, healthcare, clinical and socio-demographic information, was linked with routine data on healthcare outcomes. Factors associated with co-prescribing of opioids and gabapentinoids were examined by Chi-square testing and logistic regression, stratified by age, sex and socioeconomic class.

Results: (1) 268 citations were found from the initial search, and 15 studies were included after study selection. These studies showed a growing number of prescriptions of gabapentinoids and reports of misuse reports internationally. From the observational studies using large databases, among the patients prescribed the medicine, the misuse prevalence of pregabalin ranged from 1.0% to 9.6%, and the prevalence of gabapentin misuse was 4.8%. Patients with substance misuse disorder were more likely to experience an overdose and to have non-medical use of gabapentin and pregabalin. Other types of included studies were generally of poor quality. (2) The results from data analysis demonstrated Accident and Emergency (A&E) attendance (for any cause) and repeated hospital admission were associated with co-prescription of opioids and gabapentinoids, after controlling for the potential confounding factors such as cancer and age.

Conclusions: overall evidence implied rising prevalence of gabapentinoid prescribing, and a rising trend of gabapentinoid misuse internationally, especially among patients with a history of substance misuse. The co-prescription of opioids and gabapentinoids was found to be associated with important socio-demographic and clinical factors. These highlight the need and opportunities for research aimed at preventing gabapentinoid misuse.

Date of Award	2017
Original language	English
Supervisor	Blair Smith (Supervisor), Jennifer Watson (Supervisor) & Weihua Meng (Supervisor)