Concept
Gabapentinoids, also known as α2δ ligands, are a class of drugs that are derivatives of the inhibitory neurotransmitter gamma-Aminobutyric acid (GABA) (i.e., GABA analogues) which block α2δ subunit-containing voltage-dependent calcium channels (VDCCs). This site has been referred to as the gabapentin receptor (α2δ subunit), as it is the target of the drugs gabapentin and pregabalin. Clinically used gabapentinoids include gabapentin, pregabalin, and mirogabalin, as well as a gabapentin prodrug, gabapentin enacarbil. Additionally, phenibut has been found to act as a gabapentinoid in addition to its action of functioning as a GABAB receptor agonist. Further analogues like imagabalin are in clinical trials but have not yet been approved. Other gabapentinoids which are used in scientific research but have not been approved for medical use include atagabalin, 4-methylpregabalin and PD-217,014. Gabapentinoids are approved for the treatment of epilepsy, postherpetic neuralgia, neuropathic pain associated with diabetic neuropathy, fibromyalgia, generalized anxiety disorder, and restless legs syndrome. Some off-label uses of gabapentinoids include the treatment of insomnia, migraine, social phobia, panic disorder, mania, bipolar disorder, and alcohol withdrawal. Existing evidence on the use of gabapentinoids in chronic lower back pain is limited, and demonstrates significant risk of adverse effects, without any demonstrated benefit. The main side-effects include: a feeling of sleepiness and tiredness, decreased blood pressure, nausea, vomiting and also glaucomatous visual hallucinations. Gabapentin#Side effectsPregabalin#Side effects and Phenibut#Side effects Gabapentinoids are ligands of the auxiliary α2δ subunit site of certain (), and thereby act as inhibitors of α2δ subunit-containing VDCCs. There are two drug-binding α2δ subunits, α2δ-1 and α2δ-2, and the gabapentinoids show similar affinity for (and hence lack of selectivity between) these two sites. The gabapentinoids are selective in their binding to the α2δ VDCC subunit.
