Gabapentin for Adults with Neuropathic Pain A Review of the Clinical Efficacy and Safety
Pharmacological management of neuropathic pain (NP) includes medications such as anticonvulsants, antidepressants, serotonin noradrenaline reuptake inhibitors, opioid analgesics, cannabinoids and methadone. Gabapentin is an anticonvulsant and has been used to manage neuropathic pain. Gabapentin is not without side effects and there is also potential for misuse. Side effects associated with gabapentin include somnolence, dizziness, peripheral edema and gait disturbances. Gabapentinoids (including gabapentin) in high doses may result in sedative and psychedelic effects. Gabapentin is structurally related to the neurotransmitter gamma aminobutyric acid (GABA) but does not bind to the GABA receptors. Its mechanism of action is through binding to calcium channels and modulating the influx of calcium and thereby bestowing antiepileptic, analgesic and sedative effects. Recent research also suggests that gabapentin acts by blocking new synapse formation. Gabapentin is available in various dosages and formulations. Besides the immediate release gabapentin there is an extended release, gastro-retentive formulation and an extended release gabapentin prodrug (enacarbil) that rapidly hydrolyses to gabapentin. The purpose of this report is to review the clinical efficacy and safety of gabapentin compared with placebo in adults with neuropathic pain.