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

• Sinus Tachycardia (see Sinus Tachycardia, [[Sinus Tachycardia]])

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

• Diaphoresis (see Diaphoresis, [[Diaphoresis]])

---

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]