Thursday, September 22, 2011

Doesn't Bind GABA Receptor

A 25 year old woman with bipolar disease attempts suicide by overdosing on gabapentin. She's taken about one hundred 400mg tablets.

Challenge: What's your antidote?

3 comments:

  1. interestingly...this is one of the toxins you don't have to dialyze!
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    Doesn’t Bind GABA Receptor

    The antidote is the tincture of time. Gabapentin is actively transported by a saturable receptor in the proximal small bowel, and thus, increasing doses overwhelm the transport system and are not absorbed. The patient may have an osmotic diarrhea, but will not die from a gabapentin overdose. With regard to the title, gabapentin was designed to be structurally related to GABA but it instead binds a voltage gated calcium channel.

    Source: UpToDate.

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  2. I found this and thought it would be interesting in regards to the above case. I also think giving calcium gluconate might help with depression of the nervous system.


    CASE REPORT
    Flumazenil and Dialysis for
    Gabapentin-Induced Coma
    Toni C Butler, MD
    Resident, Department of Surgery,
    Bassett Healthcare, Cooperstown,
    NY
    Raquel M Rosen, MD
    Attending Physician, Division of
    Nephrology, Department of Adult
    and Pediatric Medicine, Bassett
    Healthcare
    Allison L Wallace , PharmD
    Pharmacy Resident, Bassett
    Healthcare
    Guy W Amsden, PharmD
    +
    Author Affiliations
    Clinical Pharmacy Specialist and
    Research Scientist, Clinical
    Pharmacology Research Center,
    Department of Adult and Pediatric
    Medicine, Bassett Healthcare
    Reprints:
    Guy W Amsden PharmD, Clinical
    Pharmacology Research Center,
    Bassett Healthcare, One Atwell Rd.,
    Cooperstown, NY 13326-1394, FAX
    607/547 -6914, E-mail
    guy.amsden @bassett.org
    -
    Navigate This Article
    Top
    Abstract
    Case Report
    Discussion
    Summary
    References
    Next Section
    Abstract
    OBJECTIVE: To describe a case of
    gabapentin-induced coma that was
    reversed with flumazenil and
    hemodialysis.
    CASE SUMMARY: We describe an 83-
    year-old dialysis-dependent white
    man who became comatose after a
    single dose of gabapentin for
    phantom limb pain. The patient was
    successfully revived from the coma
    with administration of flumazenil,
    which was then followed by
    hemodialysis. Serum concentration
    data before and 4 hours after dialysis
    document the effectiveness of
    hemodialysis for gabapentin toxicity.
    DISCUSSION: An objective causality
    assessment revealed that this adverse
    event was probably related to the
    gabapentin that the patient received.
    To our knowledge, this is the first
    documented case of not only
    gabapentin-induced coma, but also
    the effectiveness of flumazenil for
    treatment of this type of coma.
    Although therapeutic hemodialysis
    has been previously described, our
    case report is strengthened by the
    serum concentration monitoring
    accompanying it.
    CONCLUSIONS: This report
    underscores the importance of
    initiating gabapentin therapy at low
    doses in dialysis- dependent patients
    and introduces a novel treatment for
    those who experience toxicity.
    flumazenil gabapentin
    hemodialysis
    Due to its lack of significant toxicity,
    need for monitoring, and drug
    interactions, as well as its rapid onset
    of action, gabapentin is now
    commonly being used as first-line
    therapy for phantom limb pain and
    other neuropathic pain syndromes. 1
    Although transient somnolence is
    relatively common, especially in the
    elderly, more serious central nervous
    system adverse effects are rare. We
    describe an elderly, hemodialysis-
    dependent man who became
    comatose after a single dose of
    gabapentin and the unique treatment
    regimen which successfully returned
    him to his baseline mental status.
    Previous Section
    Next Section

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