Gabapentine. Pharmacology and clinical settings

Gabapentin is a structural analog of gamma-aminobutyric acid (GABA) widely used in the treatment of neuropathic pain and as an adjunct therapy in focal epilepsy. Although its structure resembles GABA, it does not act directly on classical GABAergic receptors. Its unique pharmacological profile stems from its interaction with specific subunits of voltage-dependent calcium channels, making it an effective modulator of pathological neuronal excitability. Gabapentin is a drug with a distinctive mechanism of action focused on the modulation of calcium channels through the α2δ subunit. Its predictable pharmacokinetic profile –without hepatic metabolism and with direct renal excretion– supports its safe use in multiple clinical settings, especially in neuropathic pain and epilepsy. In anxiety disorders, its use is off-label and is indicated for generalized anxiety and social anxiety; it has been shown to be especially useful in patients with comorbid chronic pain. In sleep problems, it improves sleep architecture in certain patients, particularly for insomnia secondary to pain or anxiety. In restless legs syndrome and as an alternative in cases where dopaminergic agonists are not tolerated. In the management of alcohol withdrawal syndrome, benzodiazepines (as an adjunct) and opioids (relief of withdrawal symptoms). Clinical trials that have evaluated gabapentin in patients with fibromyalgia show variable results. In general, its efficacy is considered lower than that of other drugs such as pregabalin or duloxetine, but it still represents a valid option in selected cases, especially when there is poor tolerance or insufficient response to first-line alternatives. Understanding its pharmacology allows for optimizing its use and reducing adverse events.