Gabapentin Treatment of Postural Tachycardia Syndrome (PoTS)
Condition: Postural Orthostatic Tachycardia Syndrome
MeSH terms: Postural Orthostatic Tachycardia Syndrome; Tachycardia; Syndrome
Study type: Interventional

Summary: 
      In this pilot study, the investigator will test the usefulness of gabapentin in treating some
      of the symptoms associated with POTS. Gabapentin is FDA-approved to treat epilepsy and nerve
      pain and works by reducing excessive activity in the nervous system. This medication has also
      been shown to be effective in reducing bowel discomfort in patients with irritable bowel
      syndrome, sleeplessness, and possibly migraine headache. The investigator has observed
      positive results when prescribing gabapentin off-label to alleviate photosensitivity and
      headaches in POTS patients. The aim of this pilot study is to better quantify what the
      investigator has seen and evaluate whether it merits further study in a larger group.
    

Detailed description: 
      Postural orthostatic tachycardia syndrome (POTS) is a disorder of the autonomic nervous
      system. The autonomic nervous system regulates major bodily functions, such as blood
      pressure, heart rate, body temperature and sweating. Patients with POTS experience heart
      palpitations, lightheadedness, and increased heart rate upon standing as well as other
      symptoms, such as nausea, foggy headedness or inability to concentrate, sensitivity to light,
      migraine headaches, and trouble sleeping that may occur even when these patients are not
      standing. Because many POTS symptoms are attributed to excessive activity in parts of the
      brain, the investigator would like to study whether some of these symptoms can be reduced
      with a proven seizure medication, gabapentin.

      The investigator will perform several simple tests on a group of POTS patients both before
      and after they have been treated with this drug. The tests will include non-invasive heart
      rate and blood pressure monitoring during a maneuver that requires the participant to exhale
      in a continuous manner as if blowing up a balloon, an assessment of sensitivity to light, and
      completion of several questionnaires that assess sleep behavior and sensitivity to heart,
      bowels, and bladder. Participants will take gabapentin for one week and placebo for another
      week. Neither the investigator nor the participant will know beforehand whether the
      participant is taking gabapentin or placebo. The investigator will then compare the results
      of pre-trial tests to post-trial tests to determine how effective gabapentin was at
      alleviating symptoms. If the trial is effective, the investigator expects gabapentin to
      reduce palpitations, decrease sensitivity to light, and improve sleep behavior.

      Risks of this study may include participants developing side-effects due to the drug.
      Side-effects of gabapentin may include dizziness, drowsiness, diarrhea, dry mouth,
      constipation, vomiting, loss of balance, allergic reaction, fatigue, and indigestion. If any
      side-effects occur, the investigator anticipates that they will be mild because the drug will
      be administered at a very low dose. Any side-effects that occur are expected to resolve
      quickly after stopping the medication. Furthermore, by gradually increasing the dose and
      restricting the trial to a relatively short period of time, the investigator will limit the
      risk of side-effects.

      Doctors and patients alike could benefit from this study by learning about a new use for an
      established drug to treat several of the symptoms of POTS, thereby improving patients'
      quality of life.
    

Intervention name(s): Gabapentin
Intervention type(s): Drug
Intervention description(s): Gradually increasing doses of "medication" from 100 mg on day 1 to 300 mg twice a day on day 6. On day 7, the patient received a 300-mg dose from the day 7 envelope, about two hours after a light breakfast and 1 hour before data collection. The relatively low dose and gradual titration were selected to enhance compliance and reduce adverse effects, based on a rectal mechanosensitivity study.
Intervention MeSH terms: Gabapentin
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Consented patients are randomized into one of two groups using balanced permutations generated randomization.com. Subject numbers will be ordered and placed in individually numbered, nontransparent envelopes by an independent observer. Trial medication is administered based on the randomization scheme.
Baseline data will be collected followed by a 7-day trial phase of either gabapentin or placebo on a gradually increasing dosing schedule. Post-trial data will be collected on day 7 followed by 1-week washout period and Week 3 crossover medication.
Masking: Double (Participant, Investigator)
Primary purpose: Treatment