Non-prescribed use of gabapentinoids

The gabapentinoid drugs gabapentin and pregabalin are medications used clinically across a range of neurological and psychiatric conditions. They have analgesic, anticonvulsant and anxiolytic effects. Their specific licensed indications differ, and vary across countries, but include certain neurological problems such as focal seizures, peripheral neuropathic pain, spasticity in multiple sclerosis, and muscular symptoms in motor neurone disease, and the psychological condition of generalized anxiety disorder. However, in many countries, gabapentin and pregabalin are frequently prescribed outside the terms of their market authorisations, and non-prescribed use has become widespread and troublesome in many populations. Increasing concerns regarding non-prescribed use have led some regulatory authorities to designate gabapentin and pregabalin as controlled substances, with accompanying regulations regarding prescriptions. This review describes the pharmacological properties of gabapentin and pregabalin, highlights evidence regarding efficacy and tolerability, summarises the findings of investigations of potential hazards with these drugs, and concludes with guidance on the clinical management of non-prescribed use.