Gabapentin Enacarbil (2 brand names, 1 dosage form, 1 route)
Available dosage forms: TABLET, EXTENDED RELEASE.
Routes of administration: ORAL.
Brand Names
- GABAPENTIN ENACARBIL
- HORIZANT
Contraindications
None.
Adverse Reactions
The following clinically significant adverse reactions are described in more detail in the Warnings and Precautionssection of the labeling: Effects on Driving [see Warnings and Precautions (5.1)] Somnolence/Sedation and Dizziness [see Warnings and Precautions (5.2)] Suicidal Behavior and Ideation [see Warnings and Precautions (5.4)] Increased Risk of Seizures and Other Adverse Reactions with Abrupt or Rapid Discontinuation [see Warnings and Precautions (5.5)] Respiratory Depression [see Warnings and Precautions (5.6)] Drug Reaction With Eosinophilia and Systemic Symptoms (DRESS)/Multiorgan Hypersensitivity [see Warnings and Precautions (5.7)]
Drug Interactions
Gabapentin enacarbil is released faster from HORIZANT Extended-Release tablets in the presence of alcohol. Consumption of alcohol is not recommended when taking HORIZANT [see Clinical Pharmacology (12.3)] .
Mechanism of Action
Gabapentin enacarbil is a prodrug of gabapentin and, accordingly, its therapeutic effects in RLS and PHN are attributable to gabapentin. The precise mechanism by which gabapentin is efficacious in RLS and PHN is unknown. The mechanism of action by which gabapentin is efficacious in PHN is unknown but in animal models of analgesia, gabapentin prevents allodynia (pain-related behavior in response to a normally innocuous stimulus) and hyperalgesia (exaggerated response to painful stimuli). Gabapentin prevents pain-related responses in several models of neuropathic pain in rats and mice (e.g., spinal nerve ligation models, spinal cord injury model, acute herpes zoster infection model). Gabapentin also decreases pain-related responses after peripheral inflammation (carrageenan footpad test, late phase of formalin test), but does not alter immediate pain-related behaviors (rat tail flick test, formalin footpad acute phase). The relevance of these models to human pain is not known. Gabapentin is structurally related to the neurotransmitter gamma-aminobutyric acid (GABA) but has no effect on GABA binding, uptake, or degradation. Gabapentin enacarbil and gabapentin have been tested in radioligand binding assays, and neither exhibited affinity for a number of other common receptor, ion channel, or transporter proteins. In vitrostudies have shown that gabapentin binds with high affinity to the α2δ subunit of voltage-activated calcium channels; however, the relationship of this binding to the therapeutic effects of gabapentin enacarbil in RLS and PHN is unknown.