Gabapentin [BSA]

Gabapentin is a novel antiepileptic drug (AED) that is a derivative of gamma-aminobutyric acid (GABA). Its pharmacological effects are different from those of existing antiepileptic drugs. Studies have shown that gabapentin alters GABA metabolism. Gabapentin has been shown to prevent epilepsy in several animal models and has also shown effects in animal models of spasticity, analgesia and amyotrophic sclerosis. Studies have found that gabapentin has a high affinity for novel binding sites in brain tissue and can cross some barriers in the body through amino acid transfer bodies. Compared with other anticonvulsants, gabapentin has fewer behavioural and cardiovascular side effects. Gabapentin has a similar structure to gamma-aminobutyric acid (GABA), but it is not a GABA receptor agonist. The receptor to which it binds on nerve cells in brain tissue has not yet been identified, so its mechanism of action is not known. When traditional antiepileptic drugs are ineffective or intolerable, gabapentin is often used as an adjunct. Research shows that adding gabapentin to treatment significantly reduces the frequency of seizures, has satisfactory long-term efficacy, and has fewer side effects. Once seizures are controlled, gabapentin alone is only effective in some people and is ineffective for denervation seizures.

Figure 1. Hypothetical mechanisms of action of gabapentin (GBP). (Sources: Felix R, et al. 2013)

GBP is not protein-bound, not metabolized, and does not induce or inhibit liver enzymes, so it lacks interactions with other "AEDs" or other drugs. It has the advantage of not interfering with other anticonvulsant drugs and can be used as a monotherapy or in combination with other anticonvulsant drugs. GBP also has the effects of antagonizing N-methyl-D aspartate receptors and antagonizing calcium ion channels. Its unique mechanism of action can be used to treat a variety of neurological and psychiatric diseases, such as epilepsy treatment, trigeminal neuralgia, band Herpes and perioperative treatment, etc. Unlike conventional AEDs used to treat non-epileptic conditions, GBP has low toxicity, and its favorable safety profile and lack of drug interactions make it an attractive alternative for a wide range of neurological and psychiatric disorders. GBP has been shown to be effective in relieving neuropathic pain both as monotherapy and as an adjunctive agent. GBP is as effective as TCAs (tricyclic antidepressants), and no serious adverse events have been reported. Studies have shown that compared with several other AEDs, GBP has significantly lower withdrawal rates and is best tolerated.

Epilepsy is a common disease of the nervous system. GBP was approved in 1993 for the adjunctive treatment of complex partial seizures with or without generalization. As an additional treatment drug for patients with refractory partial epilepsy, GBP also shows good efficacy as a single treatment drug for some patients with epilepsy. Postherpetic neuralgia is a complication of herpes zoster virus infection. It is a long-term persistent pain left after the herpes has healed. More than 9 to 14% of herpes zoster patients suffer from postherpetic neuralgia, and the older they are, the more likely it will occur. For those over 50 years old, it is 15-70%, and for those over 60 years old, it is as high as 50%-75%. General analgesics are ineffective, and tricyclic antidepressants and sympathetic nerve blocking drugs are also of limited effect. Clinical experimental research results show that the use of GBP can quickly relieve patients' existing pain conditions and significantly reduce patients' pain, and the clinical treatment safety of this drug is relatively high. In addition, GBP can reduce patients' central nervous system sensitization and reduce postoperative acute pain symptoms. Perioperative administration of GBP can better prevent and reduce the incidence of chronic pain in patients after cesarean section. At present, the analgesics used to treat patients in the perioperative period are often opioids combined with non-steroidal anti-inflammatory drugs, which have significant side effects on patients. In addition to good anti-allodynia and anti-hyperalgesia, GBP also has small side effects. Some studies have found that when GBP is used in the perioperative period, patients' postoperative VAS (visual analog scale for pain) is significantly reduced and their opioid consumption is significantly reduced. GBP is an alternative or auxiliary drug for the treatment of persistent pain in adults and is the first-line treatment for neuropathic pain. The American Pain Society and the American Society of Anesthesiologists also recommend GBP as a component of multimodal postoperative pain treatment. In summary, GBP is a new type of AED with a unique mechanism of action. Its oral liquid preparation has significant advantages in pediatric applications. It can not only be used to treat partial epileptic seizures and postherpetic neuralgia. In addition, because GBP has few adverse reactions and few interactions with other drugs, its favorable safety profile makes it a powerful alternative treatment option for a wide range of neurological and psychiatric disorders. The effectiveness of GBP has also been demonstrated in neuropathic pain syndromes, migraine prevention, and morphine dependence.

Neurontin
Gabarone
Gralise
Horizant
1-(Aminomethyl)cyclohexaneacetic acid
Gabapentin enacarbil