Gabapentin (Neurontin)

Indications

  • Cluster Headaches (see Headache, [[Headache]])
  • Ethanol Dependence see Ethanol, [[Ethanol]])
  • Ethanol Withdrawal (see Ethanol, [[Ethanol]]): may have a role
  • Fibromyalgia (see Fibromyalgia, [[Fibromyalgia]])
  • Migraines (see Migraines, [[Migraines]])
  • Opiate Dependence (see Opiates, [[Opiates]])
  • Partial Seizures (see Seizures, [[Seizures]]): FDA approved for this indication in 1993
  • Peripheral Neuropathy with Neuropathic Pain (see Peripheral Neuropathy, [[Peripheral Neuropathy]]) [MEDLINE]
    • Diabetic Neuropathy
    • Post-Herpetic Neuralgia
  • Psychiatric Disorders
  • Restless Legs Syndrome (see Restless Legs Syndrome, [[Restless Legs Syndrome]])
    • Gabapentin Enacarbil (Horizant)

Pharmacology

  • Structural Analog of the Inhibitory Brain Neurotransmitter γ-Aminobutyric Acid (GABA): however, gabapentin does to bind to GABA-A or GABA-B receptors (and does not affect GABA transport)
    • Gabapentin is a α-2-δ Calcium Channel Ligand Which Impairs Trafficking of This Subunit: this results in inhibition of calcium currents
    • By poorly understood mechanisms, gabapentin increases GABA levels
    • Gabapentin may also increase the activity of glutamic acid decarboxylase (GAD), an enzyme responsible for GABA synthesis

Metabolism

  • xxx

Administration

  • PO (Gabapentin for Partial Seizures): 300-1200 mg TID
  • PO (Gabapentin for Neuropathic Pain): 300-1200 mg TID
  • PO (Gabapentin for Post-Herpetic Neuralgia): 300-600 TID
  • PO (Gabapentin Enacarbil for Restless Legs Syndrome): xxxx

Dose Adjustment

  • Hepatic: none
  • Renal Dose: adjust dose and frequency

Adverse Effects

Neurologic Adverse Effects

  • Asterixis (see Asterixis, [[Asterixis]])
  • Ataxia (see Ataxia, [[Ataxia]])
  • Exacerbation of Myasthenia Gravis (see Myasthenia Gravis, [[Myasthenia Gravis]]): anecdotal reports
  • Fatigue (see Fatigue, [[Fatigue]])
  • Somnolence

Other Adverse Effects

  • xxxx
  • xxxx
  • xxxx
  • xxxx

Gabapentin Withdrawal

Epidemiology

  • xxx

Clinical

General Comments

  • May Mimic Benzodiazepine/Ethanol Withdrawal: since gabapentin augments GABA levels (similar to benzodiazepines and ethanol)

Cardiovascular Manifestations

Neurologic Manifestations

  • Akathisia (see Akathisia, [[Akathisia]])
  • Anxiety (see Anxiety, [[Anxiety]])
  • Catatonia (see Catatonia, [[Catatonia]])
  • Delirium/Confusion (see Delirium, [[Delirium]])
  • Seizures (see Seizures, [[Seizures]]): may result in status epilepticus

Other Manifestations


References

  • Rebound psychiatric and physical symptoms after gabapentin discontinuation. J Clin Psychiatry. 1998; 59:131. Letter
  • Gabapentin withdrawal syndrome. Clin Neuropharmacol. 2001; 24:245–6
  • Gabapentin withdrawal presenting as status epilepticus. J Toxicol Clin Toxicol. 2002; 40:925–8
  • Anorgasmia and withdrawal syndrome in a woman taking gabapentin. Can J Psychiatry. 2003; 48:125–6
  • Gabapentin withdrawal syndrome in the presence of a taper. Bipolar Disord. 2005; 7:302–4
  • Gabapentin abuse, and delirium tremens upon gabapentin withdrawal. J Clin Psychiatry. 2007; 68:483–4
  • Abuse, dependency and withdrawal with gabapentin: a first case report. Pharmacopsychiatry. 2007; 40:37–45
  • Withdrawal symptoms after gabapentin discontinuation. Am J Health Syst Pharm. 2010 Jun 1;67(11):910-2. doi: 10.2146/ajhp090313 [MEDLINE]
  • Gabapentin withdrawal syndrome in a post-liver transplant patient. J Pain Palliat Care Pharmacother. 2010 Sep;24(3):236-8. doi: 10.3109/15360288.2010.493927 [MEDLINE]
  • Akathisia induced by gabapentin withdrawal. Ann Pharmacother. 2011 Jun;45(6):e31. doi: 10.1345/aph.1Q057. Epub 2011 Jun 7 [MEDLINE]
  • Delirium after gabapentin withdrawal. Case report.Can J Neurol Sci. 2013 Jan;40(1):126-7 [MEDLINE]
  • Gabapentin withdrawal: case report in an older adult and review of the literature. J Am Geriatr Soc. 2013 Sep;61(9):1635-7. doi: 10.1111/jgs.12427 [MEDLINE]
  • Asterixis related to gabapentin intake: a case report and review. Postgrad Med. 2013 Sep;125(5):139-41. doi: 10.3810/pgm.2013.09.2696 [MEDLINE]
  • Gabapentin for chronic neuropathic pain and fibromyalgia in adults. Cochrane Database Syst Rev. 2014 Apr 27;4:CD007938. doi: 10.1002/14651858.CD007938.pub3 [MEDLINE]
  • The role of gabapentin in the management of alcohol withdrawal and dependence. Ann Pharmacother. 2015 Aug;49(8):897-906. doi: 10.1177/1060028015585849. Epub 2015 May 12 [MEDLINE]
  • Neonatal Gabapentin Withdrawal Syndrome. Pediatr Neurol. 2015 Nov;53(5):445-7. doi: 10.1016/j.pediatrneurol.2015.06.023. Epub 2015 Jul 8 [MEDLINE]