antidepressant agents continues to be a significant cause of treatment failure, despite the common belief that these medications are “better tolerated” (2–4).

References

1. Stahl SM. Basic psychopharmacology of antidepressants, part 1: antidepressants have seven distinct mechanisms of actions. J Clin Psychiatry 1998;59 (suppl 4):5S–14S.
2. Gumnick JF, Nemeroff CB. Problems with currently available antidepressants. J Clin Psychiatry 2000;61(suppl 10):5S–15S.
3. Fava M. Management of nonresponse and intolerance: switching strategies. J Clin Psychiatry 2000;61(suppl 2):10S–12S.
4. Zullino DF, Riquier F. Venlafaxine and vivid dreaming [letter]. J Clin Psychiatry 2000;61:600.

Michael J Robinson, MD, FRCPC
Kingston, Ontario

Dear Editor

Once patients become dependent on benzodiazepines, discontinuing them often proves vexing. Detoxification ends up being prolonged or unsuccessful due to withdrawal or re-emergent anxiety (1), as well as to the need for an external source of control (2). Gabapentin is a novel anticonvulsant, structurally analogous to gamma-aminobutyric acid (GABA), that promotes GABA release via unknown mechanisms (3). It has been reported helpful in the management of pain syndromes (4), anxiety (5–7), and alcohol withdrawal (8). We present a case wherein detoxification from benzodiazepines was aided by the use of gabapentin; there have been no previous similar reports.

Mrs A was a 49-year-old woman with a 7-year history of continuous dependence on 12 to15 mg of alprazolam daily. Tolerance, withdrawal, and loss of control characterized her use, with marked interference in her work and home life. Her benzodiazepine dependence was complicated by Fiorinal-C˝ and diphenhydramine abuse. Compounding matters was a history of recurrent panic and generalized anxiety, frequent depressive episodes with suicidality, and

somatization. She entered hospital after a suicide attempt in which she took 60 to 75 mg of alprazolam. Despite multiple somatic complaints, her physical status was unremarkable, with normal renal function.

She was continued on her previous paroxetine at 20 mg daily. Alprazolam, barbiturates, opiates, and antihistamines were stopped. A clonazepam taper was started at 2 mg twice daily, with dose as needed for breakthrough withdrawal or marked anxiety. On 1 mg of clonazepam daily her taper stalled; overwhelming anxiety, tremor, and affective instability prevented further dose reduction. Due to her instability and continued benzodiazepine use, she was declined entry into residential addiction treatment. She refused carbemazepine because of potential side effects. She instead started on 200 mg of gabapentin 3 times daily. Initially as her symptoms of anxiety, tremor, and affective lability rapidly decreased, she described gabapentin as “feeling like alprazolam.” Clonazepam was then tapered off. Within 3 weeks of admission, she was benzodiazepine-free. The subjective, alprazolam-like effect faded, but anxious symptoms remained controlled, with little craving for benzodiazepines or other substances, including cigarettes. She denied any adverse effects from the medication, except for short-term sedation. The total daily dose of gabapentin remained low (600 mg daily). Off benzodiazepines, her mental state improved, allowing discharge from hospital and commencement of outpatient addiction treatment. Two months later, she remained abstinent.

Carbemazepine has been used in benzodiazepine detoxification (1), but its potential for adverse effects necessitates close monitoring and laboratory testing. These concerns precluded its use in this case. Alternatively, prolonged benzodiazepine tapers often fail (1,9) or can obstruct entry into addiction treatment. In this case, the addition of gabapentin appeared to ease the benzodiazepine detoxification process appreciably, shortening overall withdrawal time

while sidestepping commonly encountered problems. Gabapentin has a relatively benign side-effect profile with few known drug interactions, a wide therapeutic window, does not require blood monitoring, and is not metabolized by the liver (3,4). Its use may thus offer  a reasonable alternative, beyond the currently available options, for withdrawing benzodiazepine-dependent patients.

References

1. Klein E, Colin V, Stolk J, Lenox RH. Alprazolam withdrawal in patients with panic disorder and generalized anxiety disorder: vulnerability and effect of carbemazepine. Am J Psychiatry 1994;151:1760–6.
2. Juergens SM. Benzodiazepines, other sedative, hypnotic, and anxiolytic drugs, and addiction. In: Miller NS, editor. The principles and practice of addictions in psychiatry. Philadelphia (PA): WB Saunders Company; 1997.
3. McNamara J. Drugs effective in the therapy of the epilepsies. In: Gilman AG, Rall TW, editors. Goodman and Gilman’s the pharmacologic basis of therapeutics. 9th ed. New York: Pergamon; 1996.
4. Mao J, Chen LL. Gabapentin in pain management. Anesth Analg 2000;91:680–7.
5. Pande AC, Davidson JRT, Jefferson JW, Janney CA, Katzelnick DJ, Weisler RH, and others. Treatment of social phobia with gabapentin: a placebo-controlled study. J Clin Psychopharmacol 1999;19:341–8.
6. Chouinard G, Beauclair L, Belanger MC. Gabapentin: long-term antianxiety and hypnotic effects in psychiatric patients with comorbid anxiety-related disorders [letter]. Can J Psychiatry 1998;43:305.
7. Brannon N, Labbate L, Huber M. Gabapentin treatment for posttraumatic stress disorder [letter]. Can J Psychiatry 2000;45:84.
8. Chatterjee CR, Ringold AL. A case report of reduction in alcohol craving and protection against alcohol withdrawal by gabapentin [letter]. J Clin Psychiatry 1999;60:617.
9. Rickels K, Case WG, Schweizer E, Garcia-Espana F, Fridman R. Long-term benzodiazepine users 3 years after participation in a discontinuation program. Am J Psychiatry 1991;148:757–61.

David Crockford, MD, FRCPC
William D White, MSc, MD
Bill Campbell, MD, CCFP
Calgary, Alberta