Background Gabapentin and pregabalin are two GABA analogues, example of an evergreening strategy. Both have been associated with a markedly off-label use.

Purpose To describe the extent and nature of the off-label use of gabapentin and pregabalin.

Material and methods Prospective observational study performed in a tertiary hospital. We included patients being treated with gabapentin or pregabalin at any time between June and August 2014. The variables collected were: sex, age, drug, therapeutic indication, dose and cost per patient-month (according to retail prices). These data were used to describe the rate and nature of the overall use and off-label use by drug. Data were collected through review of medical records and by electronic pharmacy refill records. Statistical analysis was performed using SPSS Statistics 20.0.

Results Sixty-five patients (54% male, mean age 60 ± 14 years) were included. Eighteen (28%) were being treated with gabapentin and 47 (28%) with pregabalin. The overall off-label use was 43% (28 patients), with no differences between the drugs (44% gabapentin and 43% pregabalin). The off-label use was related to the therapeutic indication (25 patients) or the dose (3 patients). The off-label indications for gabapentin were: central neuropathic pain (6), subacute or chronic low back pain (3), generalised anxiety disorder (3) and refractory visceral pain (1). The off-label indications for pregabalin were: subacute or chronic low back pain (6 patients), fibromyalgia (5), and essential tremor (1). The average cost per patient-month was €25 ± 11 for gabapentin and €156 ± 65 for pregabalin.

Conclusion Gabapentin and pregabalin are often prescribed for off-label use. Despite having failed to demonstrate clinically relevant differences over gabapentin, pregabalin holds a high prescription rate with consequent extra costs for the hospital, representing an area in which rational drug use could be promoted.

Reference

1. Radley DC, Finkelstein SN, Stafford RS. Off-label prescribing among office-based physicians. Arch Intern Med 2006;166:1021–6

ReferenceNo conflict of interest.